Polymerization process

ABSTRACT

The present invention relates to a continuous gas phase process comprising polymerizing one or more hydrocarbon monomer(s) in a fluidized bed reactor in the presence of a Ziegler-Natta-type catalyst system and a condensable fluid for a period of at least 12 hours where the bed temperature is less than the Critical Temperature and the dew point temperature of the gas composition in the reactor is within 25° C. of the bed temperature.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 11/515,525, filed Sep. 5,2006, now U.S. Pat. No. 7,300,987, which is a continuation of Ser. No.11/132,863, filed May 19, 2005, now U.S. Pat. No. 7,122,607, whichclaims the benefit of Ser. No. 60/572,876, filed May 20, 2004; Ser. No.60/572,786, filed May 20, 2004; and Ser. No. 60/581,463, filed Jun. 21,2004, the disclosures of which are incorporated by reference in theirentireties.

FIELD OF THE INVENTION

The present invention relates to a gas phase polymerization processoperating below the Critical Temperature.

BACKGROUND OF THE INVENTION

Advances in polymerization and catalysis have resulted in the capabilityto produce many new polymers having improved physical and chemicalproperties useful in a wide variety of superior products andapplications. With the development of new catalysts, the choice ofpolymerization-type (solution, slurry, high pressure or gas phase) forproducing a particular polymer has been greatly expanded. Also, advancesin polymerization technology have provided more efficient, highlyproductive and economically enhanced processes. Regardless of thesetechnological advances in the polyolefin industry, common problems, aswell as new challenges still exist. For example, the tendency for a gasphase process to foul and/or sheet remains a challenge, which canparticularly be dependent on the polymer being produced and the catalystsystem employed.

Fouling, sheeting and/or static generation in a continuous gas phaseprocess, in for example heat exchangers, distributor plates, and probes,can lead to the ineffective operation of various reactor systems. In atypical continuous gas phase process, a recycle system is employed formany reasons including the removal of heat generated in the process bythe polymerization reaction, and recycle processes offer manyopportunities for fouling.

Evidence of, and solutions to, various process operability problems,including fouling, sheeting, chunking, agglomerating and static buildup, have been addressed by many in the art. For example, U.S. Pat. Nos.4,792,592, 4,803,251, 4,855,370 and 5,391,657 all discuss techniques forreducing static generation in a polymerization process by introducing tothe process for example, water, alcohols, ketones, and/or inorganicchemical additives; PCT publication WO 97/14721 published Apr. 24, 1997discusses the suppression of fines that can cause sheeting by adding aninert hydrocarbon to the reactor; U.S. Pat. No. 5,066,736 and EP-A1 0549 252 discuss the introduction of an activity retarder to the reactorto reduce agglomerates; EP-A1 0 453 116 discusses the introduction ofantistatic agents to the reactor for reducing the amount of sheets andagglomerates; U.S. Pat. No. 4,012,574 discusses the addition of asurface-active compound, a per fluorocarbon group, to the reactor toreduce fouling; U.S. Pat. No. 5,026,795 discusses the addition of anantistatic agent with a liquid carrier to the polymerization zone in thereactor; U.S. Pat. No. 5,410,002 discusses using a conventionalZiegler-Natta titanium/magnesium supported catalyst system where aselection of antistatic agents are added directly to the reactor toreduce fouling; U.S. Pat. No. 3,470,143 describes a reduction in foulingin mostly slurry processes for producing primarily elastomers using afluorinated organic carbon compound.

Likewise, further evidence of, and solutions to, various processoperability problems have been addressed by many in the art. Forexample, U.S. Pat. No. 3,082,198 discusses introducing an amount of acarboxylic acid dependent on the quantity of water in a process forpolymerizing ethylene using a titanium/aluminum organ metallic catalystsin a hydrocarbon liquid medium; U.S. Pat. No. 3,919,185 describes aslurry process using a nonpolar hydrocarbon diluent with a conventionalZiegler-Natta-type or Phillips-type catalyst and a polyvalent metal saltof an organic acid having a molecular weight of at least 300; U.S. Pat.No. 5,990,251 relates to increasing catalyst activity of aZiegler-Natta-type catalyst by using very small quantities of ahalogenated hydrocarbon, specifically a molar ratio between 0.001 and0.15 of the halogenated hydrocarbon, particularly chloroform, to themetal of the catalyst, specifically titanium; U.S. Pat. No. 6,455,638 isdirected to a polymer blend having components with different ethylenecontent, and U.S. Pat. No. 5,624,878 relates primarily to the use inpolymerization of catalytic derivatives of titanium (II) and zirconium(II) misallocate-type complexes; both U.S. Pat. Nos. 6,455,638 and5,624,878 mention generally, in passing, using in polymerization varioussolvents such as straight-chain hydrocarbons, cyclic and alicyclichydrocarbons, per fluorinated hydrocarbons, aromatic andalkyl-substituted aromatic compounds, and mixtures thereof. U.S. Pat.No. 6,534,613 describes using a Ziegler-Natta-type catalyst incombination with a halogenated hydrocarbon, particularly chloroform, andan electron donor to produce polymers useful for making better qualityfilms. EP 1 323 746 shows loading of biscyclopentadienyl catalyst onto asilica support in perfluorooctane and thereafter the prepolymerizationof ethylene at room temperature. U.S. Pat. No. 3,056,771 disclosespolymerization of ethylene using TiCl₄/(Et)₃Al in a mixture of heptaneand perfluoromethylcyclohexane, presumably at room temperature.

ExxonMobil patents U.S. Pat. No. 5,352,749, U.S. Pat. No. 5,405,922, andU.S. Pat. No. 5,436,304 disclose the use of high induced condensingagent (ICA) concentrations for high condensing levels, and high (heattransfer limited) production rates in gas phase reactors. These patentsteach various means to determine the limiting concentration of ICA (suchas isopentane) that can be tolerated in the gas phase reactors withoutinducing stickiness. These patents do not note the discovery of acritical temperature, below which stickiness induced by high condensableconcentrations cannot occur.

Others have addresses stickiness prevention in gas phase reactorsincluding U.S. Pat. Nos. 5,510,433, 5,342,907, 5,194,526 and 5,037,905These patents disclose that very low density, sticky materials can beproduced in gas phase reactors by adding 10-20 wt % of inert,“refractory” material to the fluid bed. Suitable refractory materialsare micro-fine silica and carbon black. However, application of thetechnology is expensive and requires substantial investment in powderhandling equipment in the production plant.

Furthermore, it is well known that stable operation of fluidized bedreactors used in the production of polymers requires the avoidance ofconditions that lead to sticky polymer. Sticky, or cohesive polymercauses a range of problems in the gas phase reactor systems. Forexample, sticky polymer can reduce the quality of fluidization thatoccurs within the reactor, and can reduce the degree of internal mixingbelow the minimum levels required to disperse the catalyst and maintainstable temperature control. In addition, stickiness of the polymer canlead to the deposition of polymer product on the walls of the reactorexpanded section, which often leads to the formation of dome sheets(solid masses of polymer material deposited on the walls of the “dome”,or expanded section of the reactor) In many cases, these dome sheets arelarge and massive, containing as much as 100 kg of agglomerated polymer.These dome sheets eventually fall from the dome and become lodged on thedistributor plate, where they interfere with fluidization. In somecases, the dome sheets block the product discharge port, and force areactor shut-down for cleaning. For these reasons it is desirable tohave means of preventing excessive stickiness of the polymer product.

Polymer stickiness is thought to be a function of several process andproduct variables within the reactor. The relevant process variablesinclude the reaction temperature and the concentrations (or partialpressures) of condensable components such as 1-hexane and isopentane inthe reactor gas phase. In general, stickiness of the polymer is promotedby higher reaction temperature and higher condensable concentrations.Important product properties include the resin density, molecular weight(or melt index), and the molecular weight distribution (MWD). Ingeneral, stickiness of the polymer is promoted by lower resin density,lower molecular weight (higher melt index), and broader molecular weightdistribution (Mw/Mn=MWD).

Fluid bed reactors used to produce polyethylene resin are normallyoperated with a relatively high reaction temperature. For example, inthe production of a typical low density film resin (0.917 g/cc density,1 dg/min melt index) produced with misallocate or Ziegler-Nattacatalyst, the reaction temperature is typically operated at 85° C. Arelatively high reactor temperature provides for a relatively hightemperature differential over the cooling water temperature (whichtypically operates at 30 to 35° C.). This, in conventional practice, isthought to provide for maximum heat removal capability for maximumproduction rates.

It would be desirable to have a polymer production process that is freeof polymer agglomeration or stickiness. It would also be desirable tohave a process that allows higher concentrations of condensable and/orhigher dew point temperatures in the reactors for higher productionrates.

Our findings indicate that, in many cases, the operating temperaturesare too high relative to the polymer sticking temperature. Although itappears counterintuitive, we found that it is possible to reduceoperating temperatures and actually increase maximum production rates,while avoiding problems of resin stickiness.

SUMMARY OF THE INVENTION

The invention is directed to a continuous process for polymerizing oneor more hydrocarbon monomer(s), preferably a gas phase process,preferably operating in condensed mode, preferably operating with afluidized bed, for polymerizing one or more olefin(s) in the presence ofcatalyst system or polymerization catalyst and a condensable fluid,preferably a condensable fluid comprising a C3 to C10 hydrocarbon, afluorinated hydrocarbon or a combination thereof at a temperature lessthan the Critical Temperature for a period of at least 12 hourspreferably 24 hours.

This invention further relates to a continuous process, preferably a gasphase process, preferably operating in condensed mode, preferablyoperating with a fluidized bed, to polymerize one or more hydrocarbonmonomers (such as linear or branched alpha-olefins) comprising operatingthe process in an insulted gas phase reactor at a temperature less thanthe Critical Temperature.

This invention further relates to a continuous process, preferably a gasphase process, preferably operating in condensed mode, preferablyoperating with a fluidized bed, to polymerize one or more hydrocarbonmonomers (such as olefins) comprising operating the process in a gasphase reactor at a bed temperature less than the Critical Temperatureand where the dew point of the gas in the reactor is within 20° C. ofthe bed temperature.

This invention further relates to a continuous process, preferably a gasphase process, preferably operating in condensed mode, preferablyoperating with a fluidized bed, to polymerize hydrocarbon monomer(s) ina reactor, said process comprising the steps of:

-   -   (a) introducing a recycle stream into the reactor, the recycle        stream comprising one or more monomer(s);    -   (b) introducing a polymerization catalyst and a condensable        fluid into the reactor where the reactor temperature is less        than the Critical Temperature for a period of more than 24        hours;    -   (c) withdrawing the recycle stream from the reactor;    -   (d) cooling the recycle stream to form a gas phase and a liquid        phase;    -   (e) reintroducing the gas phase and the liquid phase,        separately, and/or in combination, into the reactor;    -   (f) introducing into the reactor additional monomer(s) to        replace the monomer(s) polymerized; and    -   (g) withdrawing a polymer from the reactor, preferably at a rate        of at least 50,000 lb/hour (22,700 kg/hr).

Alternately, in any embodiment herein the gas phase polymerization isoperated in a condensed mode in which a liquid and a gas are introducedto a fluidized bed reactor having a fluidizing medium, wherein the levelof condensable fluid is greater than 1 weight percent, preferablygreater than 2 weight percent, more preferably greater than 10 weightpercent, even more preferably greater than 15 weight percent, still evenmore preferably greater than 25 weight percent, and most preferablygreater than 30 weight percent up to 60 weight percent or more,preferably 35 weight percent or more, based on the total weight of theliquid and gas entering the reactor.

In any of the above processes of the invention, a preferred catalystsystem or polymerization catalyst is a conventional-type transitionmetal catalyst such as a Ziegler-Natta-type catalyst or a Phillips-typecatalyst, or a bulky legend metallocene-type catalyst.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a drawing of a typical gas phase process employing a recyclestream, where catalyst (3) and monomer feed (1) enter the gas phasereactor (7) and are swept above the distributor plate (2) into thefluidized bed mixing zone (8), provided with at least one temperaturemonitoring probe (10) where the monomer is polymerized into polymer thatis then withdrawn via a discharge apparatus (6), at the same time arecycle stream (9) is withdrawn from the reactor and passed to acompressor (4), from the compressor the recycle stream is passed to aheat exchanger (5), and thereafter the recycle stream is passed backinto the reactor along with the monomer feed (1).

FIG. 2 shows an approximation of a typical DSC melting curve of apolymer illustrating a typical reactor temperature and the limitingresin sticking temperature (Ts) relative to the DSC melting curve.

DETAILED DESCRIPTION OF THE INVENTION

The invention is generally directed toward a polymerization process,particularly a gas phase process for polymerizing one or more monomer(s)in the presence of a catalyst system. The invention also relates to apolymerization process having improved operability and productcapabilities. It has been surprisingly discovered that operating at aspecific set of conditions below the usual commercial conditions in agas phase polymerization process (e.g. below the Critical Temperature)provides for a substantially improved polymerization process and theproduction of polymers at commercially acceptable production rates.

We have found that problems associated with polymer stickiness inducedby condensable in the reactor can be significantly reduced or eveneliminated by a process involving: 1) determining the dry stickingtemperature of the polymer to be produced, 2) determining the meltingpoint depression of the polymer that occurs when a sample of the polymerto be produced is immersed in a liquid (or liquid mixture) of thecondensables to be used in the process (ICA and co monomer), 3)operating the gas phase reactor process with a bed temperature below aCritical Temperature, defined as the dry sticking temperature minusmelting point depression. With the bed temperature below the CriticalTemperature, stickiness in the resin due to high condensablesconcentrations is reduced or eliminated altogether. Hence, thecondensable concentrations in the reactor can then be raised to obtainhigher dew point temperatures, higher condensing levels, and higherproduction rates.

With the process of the present invention, the condensable concentrationin the reactor is not significantly limited by stickiness, so the dewpoint temperature can be raised to the allowable dew point limit, whichwe define as T_(DP) (max). In general, the maximum allowable dew pointtemperature will be a function of the bed temperature as well as thetemperature of the reactor walls. (The walls of the reactor normallyoperate somewhat lower than the bed temperature.) The highest allowabledew point temperatures are obtained with wall temperatures equal to thebed temperature, which is operated at or slightly below the criticaltemperature. For this reason, the use of reactors with externalinsulation is preferred in some embodiments. The external insulation maybe used in combination with heating means (electrical or steam tracingwith an associated temperature control system) to maintain the reactorwall temperatures approximately equal to the bed temperature (e.g.within 2° C. of the bed temperature or less, preferably 1° C. or less).

To better understand the instant invention, it is useful to discussstickiness in gas phase reactors. Stickiness can be induced in polymersby two means: (1) raising the temperature of the material, or (2) byincreasing the concentration of dissolved components within the polymer.In the gas phase process, the dissolved components include the highermolecular weight (higher boiling) components in the reactor gas such as,co monomers (e.g. 1-butene or 1-hexene) and induced condensing agents(ICA's). ICA's are inert condensable fluids (typically C5 or C6saturated hydrocarbons) that are added to the reactor to increase thecooling capacity of the reactor system for increased production rates.Use of ICA's is further described in U.S. Pat. Nos. 5,342,749 and5,436,304 both of which are herein fully incorporated by reference.Lower molecular weight components such as ethylene, nitrogen andhydrogen typically have only minimal solubility in the polymer, andtherefore do not tend to induce stickiness in the polymer.

FIG. 2 shows an approximation of a typical DSC melting curve of apolymer. The melting temperature TM is taken as the peak of the meltingcurve. The reactor bed temperature is normally operated considerablybelow the melting temperature as shown. For a typical LLDPE film resin(0.917 g/cc density, melt index of 1 dg/min) the melting temperature ofthe polymer is in the range of 119 to 127° C. (as measured dry, withoutdissolved components). For these grades the bed temperature wouldnormally be set at 84 to 87° C. Stickiness in the polymer would beinduced if the reactor bed temperature were increased to the point atwhich it would begin to overlap the polymer melting curve as shown inthe figure. For Ziegler-Natta catalyzed resins, stickiness occurs whenapproximately 15% overlap occurs (i.e. 15% of the crystalline fractionof the polymer melted). For metallocene catalyzed resins, a higherdegree of overlap is required to induce stickiness. While the exactnumber is not known for metallocene, it is believed to be in the rangeof 30 to 40%.

Stickiness can also be induced in the polymer product by increasing theconcentration of condensables in the reactor gas phase. The condensablesbecome dissolved in the polymer and act to depress the polymer meltcurve. Stickiness in the polymer results when the melting curve isdepressed to the point at which it overlaps the reactor operatingtemperature (the bed temperature).

Thus determination of the sticking temperature for each polymer to bemade is very useful to reactor operations. The dry sticking temperaturemust be determined in a fluid bed of the polymer to be tested operatingat substantially the same conditions as the production process, but withno condensable gases in the system and with no catalyst (i.e. noreaction). The dry sticking temperature is determined in a reactoroperating at equivalent pressure and gas velocity, but with the normalgas components replaced with substantially pure nitrogen. The vessel forthe testing has a differential pressure sensor for monitoring thepressure-difference between the bottom and the top of the fluid bed (bedDP), and DP sensors for monitoring the degree of fouling (if any) on thereactor heat exchanger, and distributor plate. The fluid bed isinitially operated at a bed temperature T_(B) of at least 40° C. belowthe peak melting temperature Tm of the polymer to be produced. The bedtemperature is then slowly increased at a rate of 2° C. per hour. Thedry sticking temperature is taken as the temperature at whichagglomerations or fouling on any surface of the vessel begins to occur(as evidenced by an increase in heat exchanger or plate DP) or thetemperature at which there is at least a 50% drop in bandwidth of thebed DP reading, which ever is the lesser temperature.

Once the dry sticking temperature of the system is determined then themelting point depression of the polymer in question is determined. Themelting point depression of the polymer (ΔTm) is determined by firstmeasuring the melting temperature of a polymer by DSC, and thencomparing this to a similar measurement on a sample of the same polymerthat has been soaked with the condensable fluid or condensable fluidmixture for a period of four hours. In general, the melting temperatureof the soaked polymer will be lower than that of the dry polymer. Thedifference in these measurements is taken as the melting pointdepression (ΔTm). Higher concentrations of dissolved materials in thepolymer cause larger depressions in the polymer melting temperature(i.e. higher values of ΔTm). A suitable DSC technique for determiningthe melting point depression is described by, P. V. Hemmingsen, “PhaseEquilibria in Polyethylene Systems”, Ph.D Thesis, Norwegian Universityof Science and Technology, March 2000. (A preferred set of conditionsfor conducting the tests are summarized on Page 112 of this reference.)The polymer melting temperature is first measured with dry polymer, andthen repeated with the polymer immersed in liquid (the condensable fluidor condensable fluid mixture to be evaluated) where the polymer has beenimmersed for four hours. As described in the reference above, it isimportant to ensure that the second part of the test, conducted in thepresence of the liquid, is done in a sealed container so that the liquidis not flashed during the test, which could introduce experimentalerror. In conventional DSC work, it is common to measure the “secondmelt” curve. This involves steps melting the polymer in a first scanthrough the DSC, cooling it back to ambient temperature, and slowlyreheating the material for the final DSC test. This second melt methodprovides improved reproducibility, but is not the preferred method forthe present work. To determine the Critical Temperature for gas phaseoperation, it is preferred to use only a single pass (or scan) in theDSC. This “first melt” data is believed to more accurately reflect thetrue melt curve of the resin as it exists in the reactor.

The actual depression of the polymer melting curve that will occur a gasphase reactor will be variable depending on the concentrations ofcondensable components in the system. Lower concentrations ofcondensables will produce smaller depressions, and higher concentrationswill produce larger depressions. In all cases, the actual depressionwill be less than or equal to the melting point depression measured in aliquid immersed sample. For hydrocarbons, we found the maximumdepression to typically about 19 to 22° C. depending on whichhydrocarbons are used.

The Critical Temperature is defined as the dry sticking temperatureminus the melting point depression (i.e. Tc=Ts (dry)−ΔTm).

If the reactor bed temperature is reduced so that it is equal to or lessthan the critical temperature, it is theoretically difficult, if notimpossible, to induce stickiness in the resin by partial melting of thepolymer, regardless of the concentration of condensable components inthe reactor system. It is therefore possible to increase the ICAconcentration to the point at which the dew point temperature of thereactor gas is equal to the bed temperature. This would producesaturation of the reactor gas with the ICA, but will not inducestickiness in the fluid bed.

However, with non-insulated reactor walls, it is not easy to operatewith a dew point temperature equal to the bed temperature. The walls ofthe reactor (i.e. the metal reactor vessel) normally operate attemperatures somewhat cooler than the fluid bed. For example, the wallsof the reactor straight section are typically 3 to 4° C. lower than thebed temperature, and the walls of the expanded section (above the fluidbed) are typically 5 to 6° C. lower than the bed temperature. In thepast, to avoid condensation on the walls of the reactor and expandedsection, it was typical to limit the dew point temperature (andcorresponding ICA concentration) to a value approximately 10-12° C. lessthan the bed temperature. Now however, we can define a maximum allowabledew point temperature as T_(DP) (max). It is the lowest of the followingthree temperatures; the reactor wall temperature (the metal temperaturein the reaction section), the reactor dome temperature, or the reactorbed temperature. Thus, the highest allowable dew point limits (andconsequently the highest allowable production rates) will be obtainedfor reactors with wall and dome temperatures approximately equal to thebed temperature. For this reason, the use of insulated reactors areextremely useful in the process of the present invention. The externalinsulation may be used in combination with heating means (electrical orsteam tracing with an associated temperature control system) to maintainthe reactor wall temperatures approximately equal to the bed temperature(e.g. within 2° C. of the bed temperature, preferably 1° C. or less). Ina preferred embodiment, if the reactor were provided with effectiveexternal insulation on both the straight section and the expandedsection (dome), the allowable dew point temperature could be raised toapproximately the bed temperature. This would provide a substantialincrease in dew point temperature and corresponding increases in maximumcondensed mode production rates compared to processes of the prior art.

Suitable insulation materials include ceramic fiber, fiberglass, andcalcium silicate. The thickness of the insulation would preferably be 1to 15 cm, and more preferably 5 to 8 cm. The insulation would preferablybe weather-proofed to prevent water incursion. Suitable weather-proofingmaterial would be metal cladding panels with sealant (or caulking)applied at the panel junctions.

Suitable instruments for measuring the reactor wall and dometemperatures include conventional wall temperature probes. These “wallTC” probes are typically mounted in stainless steel sheaths (3-6 mm indiameter) with a rounded tip that contains the thermocouple sensingelement. These probes are typically inserted through the reactor wallusing an appropriate pressure sealing (or feed through) device. Suitablefeed through devices include those manufactured by Conax Buffalo Corp.The probes are inserted through the sealing device such that the tip ofeach probe is approximately flush with the interior wall, or extendslightly (1-5 mm) past the wall into the reactor. Reactors arepreferably equipped with a number of wall TC probes to monitor walltemperatures at various positions in the reactor section and dome.

In a preferred embodiment any of the polymerization process describedherein are a continuous process. By continuous is meant a system thatoperates (or is intended to operate) without interruption or cessation.For example a continuous process to produce a polymer would be one inwhich the reactants are continuously introduced into one or morereactors and polymer product is continually withdrawn.

Alternately, the invention provides for a continuous gas phase processfor polymerizing one or more hydrocarbon monomer(s) in the presence of aconventional-type transition metal catalyst or catalyst system and acondensable fluid, preferably a C3 to C10 hydrocarbon, a fluorinatedhydrocarbon or a mixture thereof, wherein, the conventional-typetransition metal catalyst or catalyst system comprises a transitionmetal, wherein the molar ratio of the condensable fluid to thetransition metal is greater than 500:1, preferably the molar ratio is inthe range of from 900:1 to 10,000:1, preferably 1500:1 to 20,000:1, andthe reactor temperature is below the Critical Temperature, optionallyfor more than 24 hours.

Alternately, the invention is directed to a continuous gas phase processfor polymerizing one or more hydrocarbon olefin(s), preferably at leastone of which is ethylene or propylene, in the presence of apolymerization catalyst, in a fluidized bed reactor, the processoperating in a condensed mode in which a liquid and a gas are introducedto the fluidized bed reactor having a fluidizing medium, wherein thelevel of condensable fluid, preferably a C3 to C10 hydrocarbon, afluorinated hydrocarbon or a mixture thereof, is greater than 1 weightpercent, preferably greater than 2 weight percent, more preferablygreater than 10 weight percent, even more preferably greater than 15weight percent, still even more preferably greater than 25 weightpercent, and most preferably greater than 30 weight percent up to 60weight percent or more, preferably 35 weight percent or more, based onthe total weight of the liquid and gas entering the reactor, and wherethe reactor temperature is below the Critical Temperature, preferablyfor a period of more than 24 hours.

In another embodiment, the polymerization catalyst comprises a metal,and the molar ratio of the condensable fluid, to the metal is greaterthan 500:1, preferably in the range of from 900:1 to 10,000:1,preferably 1500:1 to 20,000:1.

In another embodiment, the process is further operated wherein the levelof condensable liquid is greater than 1 weight percent, preferablygreater than 2 weight percent, more preferably greater than 10 weightpercent, even more preferably greater than 15 weight percent, still evenmore preferably greater than 25 weight percent, and most preferablygreater than 30 weight percent up to 60 weight percent or more,preferably 35 weight percent or more, based on the total weight of theliquid and gas entering the reactor. In a further preferred embodiment,the conventional-type transition metal catalyst or catalyst systemcomprises a transition metal, wherein the molar ratio of the condensablefluid, preferably the fluorinated hydrocarbon, to the transition metalis greater than 500:1, preferably the molar ratio is greater than 900:1,and most preferably the molar ratio is greater than 1000:1.

In an embodiment, the invention is directed to a process, preferably acontinuous process, for polymerizing monomer(s) in a reactor, saidprocess comprising the steps of: (a) introducing a recycle stream intothe reactor, the recycle stream comprising one or more monomer(s); (b)introducing a polymerization catalyst or catalyst system and acondensable fluid into the reactor where the reactor operates at atemperature below the Critical Temperature, preferably for a period ofmore than 24 hours; (c) withdrawing the recycle stream from the reactor;(d) cooling the recycle stream to form a gas phase and a liquid phase;(e) reintroducing the gas phase and the liquid phase, separately, and/orin combination, into the reactor; (f) introducing into the reactoradditional monomer(s) to replace the monomer(s) polymerized; and (g)withdrawing a polymer product from the reactor. In a preferredembodiment, the condensable fluid is introduced in a concentrationgreater than 0.5 mole percent, preferably greater than 1 mole percent,more preferably greater than 2 mole percent, still more preferablygreater than 3 mole percent, even more preferably greater than 4 molepercent, still even more preferably greater than 5 mole percent, stilleven more preferably greater than 7 mole percent, still even morepreferably greater than 10 mole percent, still even more preferablygreater than 15 mole percent, still even more preferably greater than 20mole percent, and most preferably greater than 25 mole percent, based onthe total moles of gas in the reactor.

In any of the above processes of the invention, a preferred catalystsystem or polymerization catalyst is a conventional-type transitionmetal catalyst such as a Ziegler-Natta-type catalyst and a Phillips-typecatalyst, or a bulky ligand metallocene-type catalyst.

For purposes of this invention and the claims thereto the term “bedtemperature” is defined to mean the temperature of the fluidized bedmeasured at an elevation at least one-half of the reactor diameter abovethe distributor plate and at a radial distance at least 0.1 times thereactor diameter from the wall of the reactor.

Any of the embodiments described herein are preferably operated,(preferably continuously) with a bed temperature below the CriticalTemperature and with a dew point temperature within 25° C. of the bedtemperature (preferably within 20° C. of the bed temperature, preferablywithin 15° C. of the bed temperature, preferably within 10° C. of thebed temperature, preferably within 5° C. of the bed temperature,preferably within 4° C. of the bed temperature, preferably within 3° C.of the bed temperature, preferably within 2° C. of the bed temperature,preferably within 1° C. of the bed temperature.

Any of the embodiments described herein are preferably continuouslyoperated below the Critical Temperature for at least 12 hours,preferably at least 24 hours, preferably at least 36 hours, preferablyat least 48 hours, preferably at least 72 hours, preferably at least 7days, preferably at least 14 days, preferably at least 21 days,preferably at least 30 days.

In any of the embodiments described herein the reactor temperature ispreferably within 10° C. below the Critical Temperature, preferablywithin 5° C. below the Critical Temperature.

In another embodiment, this invention is directed to a continuousprocess for polymerizing one or more hydrocarbon monomer(s), preferablya gas phase process, preferably operating in condensed mode, preferablyoperating with a fluidized bed, for polymerizing one or more olefin(s)in the presence of catalyst system or polymerization catalyst and acondensable fluid, preferably a condensable fluid comprising a C3 to C10hydrocarbon, a fluorinated hydrocarbon or a combination thereof at atemperature less than the Z Temperature (where the Z Temperature is theheat seal initiation temperature of the polymer to be made minus themelting point depression of the polymer to be made) for a period of atleast 12 hours preferably 24 hours. Melting point depression is measuredas described above.

To determine heat seal initiation temperature, 100 kilograms of thepolymer in question are melt homogenized on a Werner Pfleiderer ModelZSK-57 twin screw extruder and pelletized. The polymer is then convertedinto a film having a thickness of 1.5 to 2.0 mils (37.5 to 50 microns)using a 1 inch Million Mini Cast Line, Model KLB 100. Heat seals aremade from the films on a laboratory scale Teller Model EB heat sealer. Adwell time of about one second and a sealing pressure of 50N/cm² areused for making the seals. The seals on the films are made in thetransverse direction and the heat sealing anvils are insulated from theheat sealing film by a Mylar® film. The Mylar® film is very stable atnormal heat sealing temperatures and is easily removed from the heatsealing polymer after the seal has been made. The seals are testedwithin 1 minute of sealing. For the strength test, the sealed samplesare cut into 0.5 inch (1.27 cm) wide pieces and then strength testedusing an Instron instrument at a crosshead speed of 20 inches/min (508mm/min) and a 2 inch (5.08 cm) jaw separation. The free ends of thesamples are fixed in the jaws, and then the jaws are separated at thestrain rate until the seal fails. The peak load at the seal break ismeasured and the seal strength is calculated by diving the peak load bythe sample width. The heat seal initiation temperature is determined bymeasuring the seal strengths of each sample sealed at varioustemperatures beginning at 50° C. below the polymer melting point (Tm)and then increasing at 2° C. intervals and then extrapolating from aplot of seal strength versus temperature to find the lowest temperatureat which at least 0.5 N/cm seal strength is present. The heat sealinitiation temperature is the lowest temperature at which at least 0.5N/cm seal strength is present.

In an alternate embodiment, in any of the embodiments described hereinthe process is operated below the Z Temperature. In an alternateembodiment of any of the embodiments described herein the process isoperated below the Z Temperature instead of below the CriticalTemperature.

In another embodiment invention is directed to a continuous process forpolymerizing one or more hydrocarbon monomer(s), preferably a gas phaseprocess, preferably operating in condensed mode, preferably operatingwith a fluidized bed, for polymerizing one or more olefin(s) in thepresence of catalyst system or polymerization catalyst and a condensablefluid, preferably a condensable fluid comprising a C3 to C10hydrocarbon, a fluorinated hydrocarbon or a combination thereof at atemperature less than the Q Temperature (where the Q Temperature is thehot tack initiation temperature of the polymer to be made minus themelting point depression of the polymer to be made) for a period of atleast 12 hours preferably 24 hours. Melting point depression is measuredas described above.

Hot tack strength is measured in accordance with the followingprocedure. The hot tack samples are 15 mm wide specimens cut from castfilms produced according to the procedure for heat seal initiationmeasurement above. The samples are back-taped (laminated) with 2 mil(approx. 50 microns) polyethylene terephthalate film to avoid rupture atthe transition of the seal and elongation or sticking to the seal bars.A Hot Tack Tester 3000, from J&B (J & B Instruments B V, Heerlen, TheNetherlands or J& B instruments USA, Inc., Spartanburg, S.C.), wasemployed to make the seal, using a seal bar pressure of 0.5 MPa, and aseal time of 0.5 sec. The hot tack force is then determined, after acooling time of 0.4 seconds and at a peel speed of 200 mm/sec. The forceat the seal break is measured and the hot tack strength is calculated bydiving the hot tack force by the sample width. Hot tack initiationtemperature is determined by measuring the hot tack strengths of eachsample sealed at various temperatures beginning at 50° C. below thepolymer melting point (Tm) and then increasing at 2° C. intervals andthen extrapolating from a plot of hot tack strength versus temperatureto find the lowest temperature at which at least 0.06 N/cm hot tackstrength is present. The hot tack initiation temperature is the lowesttemperature where an at least 0.06 N/cm hot tack strength is present.

In an alternate embodiment, in any of the embodiments described hereinthe process is operated below the Q Temperature. In an alternateembodiment of any of the embodiments described herein the process isoperated below the Q Temperature instead of below the CriticalTemperature.

Catalyst Components and Catalyst Systems

All polymerization catalysts including conventional-type transitionmetal catalysts are suitable for use in the polymerization process ofthe invention. The following is a non-limiting discussion of the variouspolymerization catalysts useful in the process of the invention. Allnumbers and references to the Periodic Table of Elements are based onthe new notation as set out in Chemical and Engineering News, 63(5), 27(1985). In the description herein the transition metal compound may bedescribed as a catalyst precursor, a transition metal catalyst, apolymerization catalyst, or a catalyst compound, and these terms areused interchangeably. The term activator is used interchangeably withthe term co-catalyst. A catalyst system is combination of a catalystcompound and an activator.

Conventional-Type Transition Metal Catalysts

Conventional-type transition metal catalysts are those traditionalZiegler-Natta-type catalysts and Phillips-type chromium catalysts wellknown in the art. Examples of conventional-type transition metalcatalysts are discussed in U.S. Pat. Nos. 4,115,639, 4,077,904,4,482,687, 4,564,605, 4,721,763, 4,879,359 and 4,960,741, all of whichare herein fully incorporated by reference. The conventional-typetransition metal catalyst compounds that may be used in the presentinvention include transition metal compounds from Groups 3 to 10,preferably 4 to 6 of the Periodic Table of Elements.

These conventional-type transition metal catalysts may be represented bythe formula:MR_(x)  (I)where M is a metal from Groups 3 to 10, preferably Group 4, morepreferably titanium; R is a halogen or a hydrocarbyloxy group; and x isthe valence of the metal M, preferably x is 1, 2,3 or 4, more preferablyx is 4. Non-limiting examples of R include alkoxy, phenoxy, bromide,chloride and fluoride. Non-limiting examples of conventional-typetransition metal catalysts where M is titanium include TiCl₃, TiCl₄,TiBr₄, Ti(OC₂H₅)₃Cl, Ti(OC₂H₅)Cl₃, Ti(OC₄H₉)₃Cl, Ti(OC₃H₇)₂Cl₂,Ti(OC₂H₅)₂Br₂, TiCl₃.⅓AlCl₃ and Ti(OC₁₂H₂₅)Cl₃.

Conventional-type transition metal catalyst compounds based onmagnesium/titanium electron-donor complexes that are useful in theinvention are described in, for example, U.S. Pat. Nos. 4,302,565 and4,302,566, which are herein fully incorporate by reference. The MgTiCl₆(ethyl acetate)₄ derivative is particularly preferred. British PatentApplication 2,105,355, herein incorporated by reference, describesvarious conventional-type vanadium catalyst compounds. Non-limitingexamples of conventional-type vanadium catalyst compounds includevanadyl trihalide, alkoxy halides and alkoxides such as VOCl₃,VOCl₂(OBu) where Bu is butyl and VO(OC₂H₅)₃; vanadium tetra-halide andvanadium alkoxy halides such as VCl₄ and VCl₃(OBu); vanadium and vanadylacetyl acetonates and chloroacetyl acetonates such as V(AcAc)₃ andVOCl₂(AcAc) where (AcAc) is an acetyl acetonate. The preferredconventional-type vanadium catalyst compounds are VOCl₃, VCl₄ andVOCl₂-OR where R is a hydrocarbon radical, preferably a C₁ to C₁₀aliphatic or aromatic hydrocarbon radical such as ethyl, phenyl,isopropyl, butyl, propyl, n-butyl, iso-butyl, tertiary-butyl, hexyl,cyclohexyl, naphthyl, etc., and vanadium acetyl acetonates.

Conventional-type chromium catalyst compounds, often referred to asPhillips-type catalysts, suitable for use in the present inventioninclude CrO₃, chromocene, silyl chromate, chromyl chloride (CrO₂Cl₂),chromium-2-ethyl-hexanoate, chromium acetylacetonate (Cr(AcAc)₃), andthe like. Non-limiting examples are disclosed in U.S. Pat. Nos.2,285,721, 3,242,099 and 3,231,550, which are herein fully incorporatedby reference.

Still other conventional-type transition metal catalyst compounds andcatalyst systems suitable for use in the present invention are disclosedin U.S. Pat. Nos. 4,124,532, 4,302,565, 4,302,566 and 5,763,723 andpublished EP-A2 0 416 815 A2 and EP-A1 0 420 436, which are all hereinincorporated by reference.

The conventional-type transition metal catalysts of the invention mayalso have the general formula:M′_(t)M″X_(2t)Y_(u)E  (II)where M′ is Mg, Mn and/or Ca; t is a number from 0.5 to 2; M″ is atransition metal such as Ti, V and/or Zr; X is a halogen, preferably Cl,Br or I; Y may be the same or different and is halogen, alone or incombination with oxygen, —NR₂, —OR, —SR, —COOR, or —OSOOR, where R is ahydrocarbyl radical, in particular an alkyl, aryl, cyclically or arylalkyl radical, acetylacetonate anion in an amount that satisfies thevalence state of M′; u is a number from 0.5 to 20; E is an electrondonor compound selected from the following classes of compounds: (a)esters of organic carboxylic acids; (b) alcohols; (c) ethers; (d)amines; (e) esters of carbonic acid; (f) nitrides; (g) phosphor amides,(h) esters of phosphoric and phosphorus acid, and (j) phosphorusoxy-chloride. Non-limiting examples of complexes satisfying the aboveformula include: MgTiCl₅.2CH₃COOC₂H₅, Mg₃Ti₂C₁₂.7CH₃COOC₂H₅,MgTiCl₅.6C₂H₅OH, MgTiCl₅.100CH₃OH, MgTiCl₅.tetrahydrofuran,MgTi₂C₁₂.7C₆H₅CN, Mg₃Ti₂Cl₁₂.6C₆H₅COOC₂H₅, MgTiCl₆.2CH₃COOC₂H₅,MgTiCl₆.6C₅H₅N, MnTiCl₅.4C₂H₅OH, MgTiCl₅(OCH₃).2CH₃COOC₂H₅,MgTiCl₅N(C₆H₅)₂.3CH₃COOC₂H₅, MgTiBr₂Cl₄.2(C₂H₅)₂O,Mg₃V₂Cl₁₂.7CH₃—COOC₂H₅, MgZrCl₆.4 tetrahydrofuran. Other catalysts mayinclude cationic catalysts such as AlCl₃, and other cobalt and ironcatalysts well known in the art.

Typically, these conventional-type transition metal catalyst compounds(excluding some conventional-type chromium catalyst compounds) areactivated with one or more of the conventional-type co catalystsdescribed below.

Conventional-Type Co catalysts

Conventional-type co catalyst compounds for the above conventional-typetransition metal catalyst compounds may be represented by the formula:M³M⁴ _(v)X² _(c)R³ _(b−c)  (III)wherein M³ is a metal from Group 1, 2, 12 and 13 of the Periodic Tableof Elements; M⁴ is a metal of Group IA of the Periodic Table ofElements; v is a number from 0 to 1; each X² is any halogen; c is anumber from 0 to 3; each R³ is a monovalent hydrocarbon radical orhydrogen; b is a number from 1 to 4; and wherein b minus c is at least1.

Other conventional-type organ metallic co catalyst compounds for theabove conventional-type transition metal catalysts have the formula:M³R³ _(k)  (IV)

where M³ is a Group 1, 2, 12 or 13 metal, such as lithium, sodium,beryllium, barium, boron, aluminum, zinc, cadmium, and gallium; k equals1, 2 or 3 depending upon the valence of M³ which valence in turnnormally depends upon the particular Group to which M³ belongs; and eachR³ may be any monovalent hydrocarbon radical.

Non-limiting examples of conventional-type organ metallic co catalystcompounds of Groups 1, 2, 12 and 13 useful with the conventional-typecatalyst compounds described above include methyl lithium, butyllithium, dihexylmercury, butyl magnesium, diethyl cadmium, benzylpotassium, diethyl zinc, tri-n-butyl aluminum, isobutyl ethyl boron,diethyl cadmium, di-n-butylzinc and tri-n-amylboron, and, in particular,the aluminum alkyls, such as tri-hexyl-aluminum, triethylaluminum,trimethylaluminum, and tri-isobutylaluminum. Other conventional-type cocatalyst compounds include mono-organ halides and hydrides of Group 2metals, and mono- or di-organohalides and hydrides of Group 13 metals.Non-limiting examples of such conventional-type co catalyst compoundsinclude di-isobutylaluminum bromide, isobutylboron dichloride, methylmagnesium chloride, ethylberyllium chloride, ethylcalcium bromide,di-isobutylaluminum hydride, methylcadmium hydride, diethylboronhydride, hexylberyllium hydride, dipropylboron hydride, octylmagnesiumhydride, butylzinc hydride, dichloroboron hydride, di-bromo-aluminumhydride and bromocadmium hydride. Conventional-type organometalliccocatalyst compounds are known to those in the art, and a more completediscussion of these compounds may be found in U.S. Pat. Nos. 3,221,002and 5,093,415, which are herein fully incorporated by reference.

For purposes of this patent specification and appended claimsconventional-type transition metal catalyst compounds exclude thosebulky ligand metallocene-type catalyst compounds discussed below. Forpurposes of this patent specification and the appended claims the term“cocatalyst” refers to conventional-type co catalysts orconventional-type organometallic cocatalyst compounds.

In some embodiment, however, it is preferred that the catalyst systemnot comprise titanium tetrachloride, particularly not the combination ofTiCl₄ and aluminum alkyl (such as triethylaluminum), particularly whenthe FC is a per fluorocarbon. In situations where the catalyst istitanium tetrachloride, particularly the combination of TiCl₄ andaluminum alkyl (such as triethylaluminum) the FC is preferably a hydrofluorocarbon. In another embodiment, the catalyst is not a free radicalinitiator, such as a peroxide.

Bulky Lipand Metallocene-Type Catalyst Compounds

Generally, polymerization catalysts useful in the invention include oneor more bulky ligand metallocene compounds (also referred to herein asmetallocenes). Typical bulky ligand metallocene compounds are generallydescribed as containing one or more bulky ligand(s) and one or moreleaving group(s) bonded to at least one metal atom. The bulky ligandsare generally represented by one or more open, acyclic, or fused ring(s)or ring system(s) or a combination thereof. These bulky ligands,preferably the ring(s) or ring system(s) are typically composed of atomsselected from Groups 13 to 16 atoms of the Periodic Table of Elements;preferably the atoms are selected from the group consisting of carbon,nitrogen, oxygen, silicon, sulfur, phosphorous, germanium, boron andaluminum or a combination thereof. Most preferably, the ring(s) or ringsystem(s) are composed of carbon atoms such as, but not limited to,those cyclopentadienyl ligands or cyclopentadienyl-type ligandstructures or other similar functioning ligand structure such as apentadiene, a cyclooctatetraendiyl or an imides ligand. The metal atomis preferably selected from Groups 3 through 15 and the lanthanide oractinide series of the Periodic Table of Elements. Preferably the metalis a transition metal from Groups 4 through 12, more preferably Groups4, 5 and 6, and most preferably the transition metal is from Group 4.

Exemplary of these bulky ligand metallocene-type catalyst compounds andcatalyst systems are described in for example, U.S. Pat. Nos. 4,530,914,4,871,705, 4,937,299, 5,017,714, 5,055,438, 5,096,867, 5,120,867,5,124,418, 5,198,401, 5,210,352, 5,229,478, 5,264,405, 5,278,264,5,278,119, 5,304,614, 5,324,800, 5,347,025, 5,350,723, 5,384,299,5,391,790, 5,391,789, 5,399,636, 5,408,017, 5,491,207, 5,455,366,5,534,473, 5,539,124, 5,554,775, 5,621,126, 5,684,098, 5,693,730,5,698,634, 5,710,297, 5,712,354, 5,714,427, 5,714,555, 5,728,641,5,728,839, 5,753,577, 5,767,209, 5,770,753 and 5,770,664 all of whichare herein fully incorporated by reference. Also, the disclosures ofEuropean publications EP-A-0 591 756, EP-A-0 520 732, EP-A-0 420 436,EP-B1 0 485 822, EP-B1 0 485 823, EP-A2-0 743 324 and EP-B1 0 518 092and PCT publications WO 91/04257, WO 92/00333, WO 93/08221, WO 93/08199,WO 94/01471, WO 96/20233, WO 97/15582, WO 97/19959, WO 97/46567, WO98/01455, WO 98/06759 and WO 98/011144 are all herein fully incorporatedby reference for purposes of describing typical bulky ligandmetallocene-type catalyst compounds and catalyst systems.

In one embodiment, the polymerization catalyst useful in the process ofthe invention includes one or more bulky ligand metallocene catalystcompounds represented by the formula:L^(A)L^(B)MQ_(n)  (V)where M is a metal atom from the Periodic Table of the Elements and maybe a Group 3 to 12 metal or from the lanthanide or actinide series ofthe Periodic Table of Elements, preferably M is a Group 4, 5 or 6transition metal, more preferably M is a Group 4 transition metal, evenmore preferably M is zirconium, hafnium or titanium. The bulky ligands,L^(A) and L^(B), are open, acyclic or fused ring(s) or ring system(s)and are any ancillary ligand system, including unsubstantiated orsubstituted, cyclopentadienyl ligands or cyclopentadienyl-type ligands,heteroatom substituted and/or heteroatom containingcyclopentadienyl-type ligands. Non-limiting examples of bulky ligandsinclude cyclopentadienyl ligands, cyclopentaphenanthreneyl ligands,indenyl ligands, benzindenyl ligands, fluorenyl ligands,octahydrofluorenyl ligands, cyclooctatetraendiyl ligands,cyclopentacyclododecene ligands, azenyl ligands, azulene ligands,pentalene ligands, phosphoyl ligands, phosphinimine (WO 99/40125),payroll ligands, pyrozolyl ligands, carbazolyl ligands, borabenzeneligands and the like, including hydrogenated versions thereof, forexample tetrahydroindenyl ligands. In one embodiment, L^(A) and L^(B)may be any other ligand structure capable of π-bonding to M. In yetanother embodiment, the atomic molecular weight (MW) of L^(A) or L^(B)exceeds 60 a.m.u., preferably greater than 65 a.m.u. In anotherembodiment, L^(A) and L^(B) may comprise one or more heteroatoms, forexample, nitrogen, silicon, boron, germanium, sulfur and phosphorous, incombination with carbon atoms to form an open, acyclic, or preferably afused, ring or ring system, for example, a hetero-cyclopentadienylancillary ligand. Other L^(A) and L^(B) bulky ligands include but arenot limited to bulky amides, phosphides, alkoxides, aryloxides, imides,carbolides, borollides, porphyrins, phthalocyanines, coring and otherpolyazomacrocycles. Independently, each L^(A) and L^(B) may be the sameor different type of bulky ligand that is bonded to M. In one embodimentof Formula V only one of either L^(A) or L^(B) is present.

Independently, each L^(A) and L^(B) may be unsubstituted or substitutedwith a combination of substituent groups R. Non-limiting examples ofsubstituent groups R include one or more from the group selected fromhydrogen, or linear, branched alkyl radicals, or alkenyl radicals,alkynyl radicals, cycloalkyl radicals or aryl radicals, acyl radicals,aroyl radicals, alkoxy radicals, aryloxy radicals, alkylthio radicals,dialkylamino radicals, alkoxycarbonyl radicals, aryloxycarbonylradicals, carbomoyl radicals, alkyl- or dialkyl- carbamoyl radicals,acyloxy radicals, acylamino radicals, aroylamino radicals, straight,branched or cyclic, alkylene radicals, or combination thereof. In apreferred embodiment, substituent groups R have up to 50 non-hydrogenatoms, preferably from 1 to 30 carbon, that can also be substituted withhalogens or heteroatoms or the like. Non-limiting examples of alkylsubstituents R include methyl, ethyl, propyl, butyl, pentyl, hexyl,cyclopentyl, cyclohexyl, benzyl or phenyl groups and the like, includingall their isomers, for example tertiary butyl, isopropyl, and the like.Other hydrocarbyl radicals include fluoromethyl, fluoroethyl,difluoroethyl, iodopropyl, bromohexyl, chlorobenzyl and hydrocarbylsubstituted organometalloid radicals including trimethylsilyl,trimethylgermyl, methyldiethylsilyl and the like; andhalocarbyl-substituted organometalloid radicals includingtris(trifluoromethyl)-silyl, methyl-bis(difluoromethyl)silyl,bromomethyldimethylgermyl and the like; and disubstitiuted boronradicals including dimethylboron for example; and disubstitutedpnictogen radicals including dimethylamine, dimethylphosphine,diphenylamine, methylphenylphosphine, halogen radicals includingmetonym, ethoxy, propoxy, phenoxy, methylsulfide and ethyl sulfide.Non-hydrogen substituents R include the atoms carbon, silicon, boron,aluminum, nitrogen, phosphorous, oxygen, tin, sulfur, germanium and thelike, including olefins such as but not limited to olefinicallyunsaturated substituents including vinyl-terminated ligands, for examplebut-3-enyl, prop-2-enyl, hex-5-enyl and the like. Also, at least two Rgroups, preferably two adjacent R groups, are joined to form a ringstructure having from 3 to 30 atoms selected from carbon, nitrogen,oxygen, phosphorous, silicon, germanium, aluminum, boron or acombination thereof. Also, a substituent group R group such as 1-butanylmay form a carbon sigma bond to the metal M.

Other ligands may be bonded to the metal M, such as at least one leavinggroup Q. In one embodiment, Q is a monoanionic labile ligand having asigma-bond to M. Depending on the oxidation state of the metal, thevalue for n is 0, 1 or 2 such that Formula V above represents a neutralbulky ligand metallocene catalyst compound.

Non-limiting examples of Q ligands include weak bases such as amines,phosphates, ethers, carboxylates, dynes, hydrocarbyl radicals havingfrom 1 to 20 carbon atoms, hydrides or halogens and the like or acombination thereof. In another embodiment, two or more Q's form a partof a fused ring or ring system. Other examples of Q ligands includethose substituents for R as described above and including cyclobutyl,cyclohexyl, heptyl, tolyl, trifluoromethyl, tetramethylene,pentamethylene, methylidene, methyoxy, ethyoxy, propoxy, phenoxy,bis(N-methylanilide), dimethylamide, dimethylphosphide radicals and thelike.

In another embodiment, the polymerization catalysts useful in theprocess of the invention may include one or more bulky ligandmetallocene catalyst compounds where L^(A) and L^(B) of Formula V arebridged to each other by at least one bridging group, A, as representedby:L^(A)AL^(B)MQ_(n)  (VI)wherein L^(A), L^(B), M, Q and n are as defined above. These compoundsof Formula VI are known as bridged, bulky ligand metallocene catalystcompounds. Non-limiting examples of bridging group A include bridginggroups containing at least one Group 13 to 16 atom, often referred to asa divalent moiety such as but not limited to at least one of a carbon,oxygen, nitrogen, silicon, aluminum, boron, germanium and tin atom or acombination thereof. Preferably bridging group A contains a carbon,silicon or germanium atom, most preferably A contains at least onesilicon atom or at least one carbon atom. The bridging group A may alsocontain substituent groups R as defined above including halogens andiron. Non-limiting examples of bridging group A may be represented byR′₂C, R′₂Si, R′₂Si R′₂Si, R′₂Ge, R′P, where R′ is independently, aradical group which is hydride, hydrocarbyl, substituted hydrocarbyl,halocarbyl, substituted halocarbyl, hydrocarbyl-substitutedorganometalloid, halocarbyl-substituted organometalloid, disubstitutedboron, disubstituted pnictogen, substituted chalcogen, or halogen or twoor more R′ may be joined to form a ring or ring system. In oneembodiment, the bridged, bulky ligand metallocene catalyst compounds ofFormula VI have two or more bridging groups A (EP-B1-0 664 301, which isincorporated herein by reference).

In another embodiment, the bulky ligand metallocene catalyst compoundsare those where the R substituents on the bulky ligands L^(A) and L^(B)of Formulas V and VI are substituted with the same or different numberof substituents on each of the bulky ligands. In another embodiment, thebulky ligands L^(A) and L^(B) of Formulas V and VI are different fromeach other.

Other bulky ligand metallocene catalyst compounds and catalyst systemsuseful in the invention may include those described in U.S. Pat. Nos.5,064,802, 5,145,819, 5,149,819, 5,243,001, 5,239,022, 5,276,208,5,296,434, 5,321,106, 5,329,031, 5,304,614, 5,677,401, 5,723,398,5,753,578, 5,854,363, 5,856,547, 5,858,903, 5,859,158, 5,900,517 and5,939,503 and PCT publications WO 93/08221, WO 93/08199, WO 95/07140, WO98/11144, WO 98/41530, WO 98/41529, WO 98/46650, WO 99/02540 and WO99/14221 and European publications EP-A-0 578 838, EP-A-0 638 595,EP-B-0 513 380, EP-A1-0 816 372, EP-A2-0 839 834, EP-B1-0 632 819,EP-B1-0 748 821 and EP-B1-0 757 996, all of which are herein fullyincorporated by reference.

In another embodiment, the catalyst compositions of the invention mayinclude bridged heteroatom, mono-bulky ligand metallocene compounds.These types of catalysts and catalyst systems are described in, forexample, PCT publication WO 92/00333, WO 94/07928, WO 91/04257, WO94/03506, WO96/00244, WO 97/15602 and WO 99/20637 and U.S. Pat. Nos.5,057,475, 5,096,867, 5,055,438, 5,198,401, 5,227,440 and 5,264,405 andEuropean publication EP-A-0 420 436, all of which are herein fullyincorporated by reference.

In another embodiment, the polymerization catalyst useful in the processof the invention includes one or more bulky ligand metallocene catalystcompounds represented by Formula VII:L^(C)AJMQ_(n)  (VII)where M is a Group 3 to 16 metal atom or a metal selected from the Groupof actinides and lanthanides of the Periodic Table of Elements,preferably M is a Group 4 to 12 transition metal, and more preferably Mis a Group 4, 5 or 6 transition metal, and most preferably M is a Group4 transition metal in any oxidation state, especially titanium; L^(C) isa substituted or unsubstituted bulky ligand bonded to M; J is bonded toM; A is bonded to J and L^(C); J is a heteroatom ancillary ligand; and Ais a bridging group; Q is a univalent anionic ligand; and n is theinteger 0, 1 or 2. In Formula VII above, L^(C), A and J form a fusedring system.

In Formula VII, J is a heteroatom containing ligand in which J is anelement with a coordination number of three from Group 15 or an elementwith a coordination number of two from Group 16 of the Periodic Table ofElements. Preferably J contains a nitrogen, phosphorus, oxygen or sulfuratom with nitrogen being most preferred. In a preferred embodiment, whenthe catalyst system comprises compounds represented by Formula VII, thefluorocarbon preferably is a hydrofluorocarbon. Preferably, when thecatalyst system comprises compounds represented by Formula VII, thefluorocarbon is not a perfluorocarbon.

In an embodiment of the invention, the bulky ligand metallocene catalystcompounds are heterocyclic ligand complexes where the bulky ligands, thering(s) or ring system(s), include one or more heteroatoms or acombination thereof. Non-limiting examples of heteroatoms include aGroup 13 to 16 element, preferably nitrogen, boron, sulfur, oxygen,aluminum, silicon, phosphorous and tin. Examples of these bulky ligandmetallocene catalyst compounds are described in PCT Publication Nos. WO96/33202, WO 96/34021, WO 97/17379 and WO 98/22486 and EP-A1-0 874 005and U.S. Pat. Nos. 5,233,049, 5,539,124, 5,554,775, 5,637,660,5,744,417, 5,756,611 and 5,856,258 all of which are herein incorporatedby reference.

In another embodiment, the bulky ligand metallocene catalyst compound isa complex of a metal, preferably a transition metal, a bulky ligand,preferably a substituted or unsubstituted pi-bonded ligand, and one ormore heteroallyl moieties, such as those described in U.S. Pat. Nos.5,527,752 and 5,747,406 and EP-B1-0 735 057, all of which are hereinfully incorporated by reference.

In another embodiment, the polymerization catalysts useful in theprocess of the invention includes one or more bulky ligand metallocenecatalyst compounds represented by Formula VIII:L^(D)MQ₂(YZ)X_(n)  (VIII)where M is a Group 3 to 16 metal, preferably a Group 4 to 12 transitionmetal, and most preferably a Group 4, 5 or 6 transition metal; L^(D) isa bulky ligand that is bonded to M; each Q is independently bonded to Mand Q₂(YZ) forms a ligand, preferably a unicharged polydentate ligand;or Q is a univalent anionic ligand also bonded to M; X is a univalentanionic group when n is 2 or X is a divalent anionic group when n is 1;n is 1 or 2.

In Formula VIII, L and M are as defined above for Formula V. Q is asdefined above for Formula V, preferably Q is selected from the groupconsisting of —O—, —NR—, —CR2— and —S—; Y is either C or S; Z isselected from the group consisting of —OR, —NR2, —CR3, —SR, —SiR3, —PR2,—H, and substituted or unsubstituted aryl groups, with the proviso thatwhen Q is —NR— then Z is selected from one of the group consisting of—OR, —NR2, —SR, —SiR3, —PR2 and —H; R is selected from a groupcontaining carbon, silicon, nitrogen, oxygen, and/or phosphorus,preferably where R is a hydrocarbon group containing from 1 to 20 carbonatoms, most preferably an alkyl, cycloalkyl, or an aryl group; n is aninteger from 1 to 4, preferably 1 or 2; X is a univalent anionic groupwhen n is 2 or X is a divalent anionic group when n is 1; preferably Xis a carbonate, carboxylate, or other heteroallyl moiety described bythe Q, Y and Z combination.

Still other useful polymerization catalysts include those multinuclearmetallocene catalysts as described in PCT Publication No. WO 99/20665and U.S. Pat. No. 6,010,794, and transition metal metaaracyle structuresdescribed in EP-A2-0 969 101, which are herein incorporated herein byreference. Other metallocene catalysts include those described inEP-A1-0 950 667, double cross-linked metallocene catalysts (EP-A1-0 970074), tethered metallocenes (EP-A2-0 970 963) and those sulfonylcatalysts described in U.S. Pat. No. 6,008,394, which are incorporatedherein by reference.

It is also contemplated that in one embodiment the bulky ligandmetallocene catalysts, described above, include their structural oroptical or elastomeric isomers (meso and racemic isomers, for examplesee U.S. Pat. No. 5,852,143, incorporated herein by reference), chiral,choral, and mixtures thereof.

In another embodiment, the bulky ligand type metallocene-type catalystcompound is a complex of a transition metal, a substituted orunsubstituted pi-bonded ligand, and one or more heteroallyl moieties,such as those described in U.S. Pat. Nos. 5,527,752 and 5,747,406 andEP-B1-0 735 057, all of which are herein fully incorporated byreference.

In one embodiment, the bulky ligand metallocene catalyst compounds arethose complexes known as transition metal catalysts based on bidentateligands containing pyridine or quinoline moieties, such as thosedescribed in U.S. application Ser. No. 09/103,620 filed Jun. 23, 1998,which is herein incorporated by reference. In another embodiment, thebulky ligand metallocene catalyst compounds are those described in PCTPublications Nos. WO 96/33202, WO 99/01481 and WO 98/42664, and U.S.Pat. No. 5,637,660, which are fully incorporated herein by reference.

In one embodiment, these catalyst compounds are represented by theformula:((Z)XA_(t)(YJ))_(q)MQ_(n)  (IX)where M is a metal selected from Group 3 to 13 or lanthanide andactinide series of the Periodic Table of Elements; Q is bonded to M andeach Q is a monovalent, bivalent, or trivalent anion; X and Y are bondedto M; one or more of X and Y are heteroatoms, preferably both X and Yare heteroatoms; Y is contained in a heterocyclic ring J, where Jcomprises from 2 to 50 non-hydrogen atoms, preferably 2 to 30 carbonatoms; Z is bonded to X, where Z comprises 1 to 50 non-hydrogen atoms,preferably 1 to 50 carbon atoms, preferably Z is a cyclic groupcontaining 3 to 50 atoms, preferably 3 to 30 carbon atoms; t is 0 or 1;when t is 1, A is a bridging group joined to at least one of X, Y or J,preferably X and J; q is 1 or 2; n is an integer from 1 to 4 dependingon the oxidation state of M. In one embodiment, where X is oxygen orsulfur then Z is optional.

In another embodiment, where X is nitrogen or phosphorous then Z ispresent. In an embodiment, Z is preferably an aryl group, morepreferably a substituted aryl group.

In another embodiment of the invention the bulky ligand metallocene-typecatalyst compounds are those nitrogen containing heterocyclic ligandcomplexes, also known as transition metal catalysts based on bidentateligands containing pyridine or quinoline moieties, such as thosedescribed in WO 96/33202, WO 99/01481 and WO 98/42664 and U.S. Pat. No.5,637,660, which are herein all incorporated by reference.

It is within the scope of this invention, in one embodiment, thepolymerization catalysts useful in the process of the invention includecomplexes of Ni²⁺ and Pd²⁺ described in the articles Johnson, et al.,“New Pd(II)- and Ni(II)-Based Catalysts for Polymerization of Ethyleneand a-Olefins”, J. Am. Chem. Soc. 1995, 117, 6414-6415 and Johnson, etal., “Copolymerization of Ethylene and Propylene with FunctionalizedVinyl Monomers by Palladium(II) Catalysts”, J. Am. Chem. Soc., 1996,118, 267-268, and WO 96/23010 published Aug. 1, 1996, WO 99/02472, U.S.Pat. Nos. 5,852,145, 5,866,663 and 5,880,241, which are all herein fullyincorporated by reference. These complexes can be either dialkyl etheradducts, or alkylated reaction products of the described dihalidecomplexes that can be activated to a cationic state by the activators ofthis invention described below.

Also included as bulky ligand metallocene-type catalyst compounds usefulherein are those diimine based ligands for Group 8 to 10 metal compoundsdisclosed in PCT publications WO 96/23010 and WO 97/48735 and Gibson,et. al., Chem. Comm., pp. 849-850 (1998), all of which are hereinincorporated by reference.

Other bulky ligand metallocene-type catalysts useful herein are thoseGroup 5 and 6 metal imido complexes described in EP-A2-0 816 384 andU.S. Pat. No. 5,851,945, which is incorporated herein by reference. Inaddition, bulky ligand metallocene-type catalysts useful herein includebridged bis(arylamido) Group 4 compounds described by D. H. McConville,et al., in Organometallics 1195, 14, 5478-5480, which is hereinincorporated by reference. Other bulky ligand metallocene-type catalystsuseful herein are described as bis(hydroxyl aromatic nitrogen ligands)in U.S. Pat. No. 5,852,146, which is incorporated herein by reference.Other metallocene-type catalysts containing one or more Group 15 atomsuseful herein include those described in WO 98/46651, which is hereinincorporated herein by reference. Still another metallocene-type bulkyligand metallocene-type catalysts useful herein include thosemultinuclear bulky ligand metallocene-type catalysts as described in WO99/20665, which is incorporated herein by reference. In addition, usefulGroup 6 bulky ligand metallocene catalyst systems are described in U.S.Pat. No. 5,942,462, which is incorporated herein by reference.

It is contemplated in some embodiments, that the bulky ligands of themetallocene-type catalyst compounds of the invention described above maybe asymmetrically substituted in terms of additional substituents ortypes of substituents, and/or unbalanced in terms of the number ofadditional substituents on the bulky ligands or the bulky ligandsthemselves are different.

Mixed Catalysts

It is also within the scope of this invention that the above describedbulky ligand metallocene-type catalyst compounds can be combined withone or more of the conventional-type transition metal catalystscompounds with one or more co-catalysts or activators or activationmethods described above. For example, see U.S. Pat. Nos. 4,937,299,4,935,474, 5,281,679, 5,359,015, 5,470,811, and 5,719,241, all of whichare fully incorporated herein by reference.

In another embodiment of the invention one or more bulky ligandmetallocene-type catalyst compounds or catalyst systems may be used incombination with one or more conventional-type catalyst compounds orcatalyst systems. Non-limiting examples of mixed catalysts and catalystsystems are described in U.S. Pat. Nos. 4,159,965, 4,325,837, 4,701,432,5,124,418, 5,077,255, 5,183,867, 5,391,660, 5,395,810, 5,691,264,5,723,399 and 5,767,031 and PCT Publication WO 96/23010 published Aug.1, 1996, all of which are herein fully incorporated herein by reference.

It is further contemplated that two or more conventional-type transitionmetal catalysts may be combined with one or more conventional-type cocatalysts. Non-limiting examples of mixed conventional-type transitionmetal catalysts are described in for example U.S. Pat. Nos. 4,154,701,4,210,559, 4,263,422, 4,672,096, 4,918,038, 5,198,400, 5,237,025,5,408,015 and 5,420,090, all of which are herein incorporated byreference.

Activator and Activation Methods

The above described polymerization catalysts, particularly bulky ligandmetallocene-type catalyst, are typically activated in various ways toyield polymerization catalysts having a vacant coordination site thatwill coordinate, insert, and polymerize olefin(s).

For the purposes of this invention, the term “activator” is defined tobe any compound which can activate any one of the polymerizationcatalyst compounds described herein by converting the neutralpolymerization catalyst compound to a catalytically active catalystaction compound. Non-limiting activators, for example, includealuminates, aluminum alkyls, ionizing activators, which may be neutralor ionic, and conventional-type co catalysts.

Aluminates

In one embodiment, leucoxene activators are utilized as an activatorwith the polymerization catalysts useful in the process of theinvention. Aluminates are generally oligomeric compounds containing—Al(R)—O— subunits, where R is an alkyl group. Non-limiting examples ofaluminates include methylalumoxane (MAO), modified methylalumoxane(MMAO), ethylalumoxane and isobutylalumoxane. Alumoxanes may be producedby the hydrolysis of the respective trialkylaluminum compound. MMAO maybe produced by the hydrolysis of trimethylaluminum and a highertrialkylaluminum such as triisobutylaluminum. MMAO's are generally moresoluble in aliphatic solvents and more stable during storage. There area variety of methods for preparing alumoxane and modified alumoxanes,non-limiting examples of which are described in U.S. Pat. Nos.4,665,208, 4,952,540, 5,091,352, 5,206,199, 5,204,419, 4,874,734,4,924,018, 4,908,463, 4,968,827, 5,308,815, 5,329,032, 5,248,801,5,235,081, 5,157,137, 5,103,031, 5,391,793, 5,391,529, 5,693,838,5,731,253, 5,731,451, 5,744,656, 5,847,177, 5,854,166, 5,856,256 and5,939,346 and European publications EP-A-0 561 476, EP-B1-0 279 586,EP-A-0 594-218 and EP-B1-0 586 665, and PCT publications WO 94/10180 andWO 99/15534, all of which are herein fully incorporated by reference.Another alumoxane is a modified methyl alumoxane (MMAO) cocatalyst type3 A (commercially available from Akzo Chemicals, Inc. under the tradename Modified Methylalumoxane type 3 A; see U.S. Pat. No. 5,041,584).Aluminum alkyl or organoaluminum compounds which may be utilized asactivators include trimethylaluminum, triethylaluminum,triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum and thelike.

Ionizing Activators

It is within the scope of this invention to use an ionizing orstoichiometric activator, neutral or ionic, such as tri (n-butyl)ammonium tetrakis (pentafluorophenyl) boron, a trisperfluorophenyl boronmetalloid precursor or a trisperfluoronaphtyl boron metalloid precursor,polyhalogenated heteroborane anions (WO 98/43983), boric acid (U.S. Pat.No. 5,942,459) or combination thereof. It is also within the scope ofthis invention to use neutral or ionic activators alone or incombination with alumoxane or modified alumoxane activators.

Non-limiting examples of neutral stoichiometric activators includetri-substituted boron, tellurium, aluminum, gallium and indium ormixtures thereof. The three substituent groups are each independentlyselected from alkyls, alkenyls, halogen, substituted alkyls, aryls, arylhalides, alkoxy and halides. Preferably, the three groups areindependently selected from halogen, mono or multicyclic (including halosubstituted) aryls, alkyls, and alkenyl compounds and mixtures thereof,preferred are alkenyl groups having 1 to 20 carbon atoms, alkyl groupshaving 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atomsand aryl groups having 3 to 20 carbon atoms (including substitutedaryls). More preferably, the three groups are alkyls having 1 to 4carbon groups, phenyl, napthyl or mixtures thereof. Even morepreferably, the three groups are halogenated, preferably fluorinated,aryl groups. Most preferably, the neutral stoichiometric activator istrisperfluorophenyl boron or trisperfluoronapthyl boron.

Ionic stoichiometric activator compounds for the polymerizationcatalysts described above may contain an active proton, or some otheraction associated with, but not coordinated to, or only looselycoordinated to, the remaining ion of the ionizing compound. Suchcompounds and the like are described in European publications EP-A-0 570982, EP-A-0 520 732, EP-A-0 495 375, EP-B1-0 500 944, EP-A-0 277 003 andEP-A-0 277 004, and U.S. Pat. Nos. 5,153,157, 5,198,401, 5,066,741,5,206,197, 5,241,025, 5,384,299 and 5,502,124 and U.S. patentapplication Ser. No. 08/285,380, filed Aug. 3, 1994, all of which areherein fully incorporated by reference.

In a preferred embodiment, the stoichiometric activators include aaction and an anion component, and may be represented by the followingformula:(L-H)_(d) ⁺.(A^(d−))  (X)wherein: L is a neutral Lewis base; H is hydrogen; (L-H)⁺ is a Bronstedacid; A^(d−) is a non-coordinating anion having the charge d−; and d isan integer from 1 to 3. The cation component, (L-H)_(d) ⁺ may includeBronsted acids such as protons or prorogated Lewis bases or reduciblecatalysts capable of prorogating or abstracting a moiety, such as analkyl or aryl, from the bulky ligand metallocene or Group 15 containingtransition metal catalyst precursor, resulting in a cationic transitionmetal species.

The activating cation (L-H)_(d) ⁺ may be a Bronsted acid, capable ofdonating a proton to the transition metal catalytic precursor resultingin a transition metal cation, including ammoniums, oxoniums,phosphoniums, silyliums and mixtures thereof, preferably ammoniums ofmethylamine, aniline, dimethylamine, diethylamine, N-methylaniline,diphenylamine, trimethylamine, triethylamine, N,N-dimethylaniline,methyldiphenylamine, pyridine, p-bromo N,N-dimethylaniline,p-nitro-N,N-dimethylaniline, phosphoniums from triethylphosphine,triphenylphosphine, and diphenylphosphine, oxomiuns from ethers such asdimethyl ether diethyl ether, tetrahydrofuran and dioxane, sulfoniumsfrom thioethers, such as diethyl thioethers and tetrahydrothiophene andmixtures thereof. The activating cation (L-H)_(d) ⁺ may also be anabstracting moiety such as silver, carboniums, tropylium, carbeniums,ferroceniums and mixtures, preferably carboniums and ferroceniums. Mostpreferably (L-H)_(d) ⁺ is triphenyl carbonium.

The anion component A^(d−) includes those having the formula[M^(k+)Q_(n)]^(d−) wherein k is an integer from 1 to 3; n is an integerfrom 2-6; n−k=d; M is an element selected from Group 13 of the PeriodicTable of the Elements, preferably boron or aluminum, and Q isindependently a hydride, bridged or unbridged dialkylamido, halide,alkoxide, aryloxide, hydrocarbyl, substituted hydrocarbyl, halocarbyl,substituted halocarbyl, and halosubstituted-hydrocarbyl radicals, said Qhaving up to 20 carbon atoms with the proviso that in not more than 1occurrence is Q a halide. Preferably, each Q is a fluorinatedhydrocarbyl group having 1 to 20 carbon atoms, more preferably each Q isa fluorinated aryl group, and most preferably each Q is a pentafluorylaryl group. Examples of suitable A^(d−) also include diboron compoundsas disclosed in U.S. Pat. No. 5,447,895, which is fully incorporatedherein by reference.

Most preferably, the ionic stoichiometric activator (L-H)_(d) ⁺.(A^(d−))is N,N-dimethylanilinium tetra(perfluorophenyl)borate ortriphenylcarbenium tetra(perfluorophenyl)borate.

In one embodiment, an activation method using ionizing ionic compoundsnot containing an active proton but capable of producing a bulky ligandmetallocene catalyst cation and their non-coordinating anion are alsocontemplated, and are described in EP-A-0 426 637, EP-A-0 573 403 andU.S. Pat. No. 5,387,568, which are all herein incorporated by reference.

Additional Activators

Other activators include those described in PCT Publication No. WO98/07515 such as tris (2,2′, 2″-nonafluorobiphenyl)fluoroaluminate,which publication is fully incorporated herein by reference.Combinations of activators are also contemplated by the invention, forexample, alumoxanes and ionizing activators in combinations, see forexample, EP-B1 0 573 120, PCT Publications Nos. WO 94/07928 and WO95/14044 and U.S. Pat. Nos. 5,153,157 and 5,453,410, all of which areherein fully incorporated by reference.

Other suitable activators are disclosed in PCT Publication No. WO98/09996, incorporated herein by reference, which describes activatingbulky ligand metallocene catalyst compounds with perchlorates, peroratesand iodates including their hydrates. WO 98/30602 and WO 98/30603,incorporated by reference, describe the use of lithium(2,2′-bisphenyl-ditrimethylsilicate).4THF as an activator for a bulkyligand metallocene catalyst compound. PCT Publication No. WO 99/18135,incorporated herein by reference, describes the use oforgano-boron-aluminum activators. EP-B1-0 781 299 describes using asilylium salt in combination with a non-coordinating compatible anion.Also, methods of activation such as using radiation (see EP-B1-0 615 981herein incorporated by reference), electro-chemical oxidation, and thelike are also contemplated as activating methods for the purposes ofrendering the neutral bulky ligand metallocene catalyst compound orprecursor to a bulky ligand metallocene cation capable of polymerizingolefins.

Other activators or methods for activating a bulky ligand metallocenecatalyst compound are described in for example, U.S. Pat. Nos.5,849,852, 5,859,653 and 5,869,723 and WO 98/32775, WO 99/42467(dioctadecylmethylammonium-bis(tris(pentafluorophenyl)borane)benzimidazolide), which are herein incorporated by reference.

Another suitable ion forming, activating cocatalyst comprises a salt ofa cationic oxidizing agent and a noncoordinating, compatible anionrepresented by the formula:(OX^(e+))_(d)(A^(d−))_(e)  (XII)wherein: OX^(e+) is a cationic oxidizing agent having a charge of e+; eis an integer from 1 to 3; and A⁻, and d are as previously definedabove. Non-limiting examples of cationic oxidizing agents include:ferrocenium, hydrocarbyl-substituted ferrocenium, Ag⁺, or Pb⁺².Preferred embodiments of A^(d−) are those anions previously defined withrespect to the Bronsted acid containing activators, especiallytetrakis(pentafluorophenyl)borate.

It within the scope of this invention that any of the polymerizationcatalysts described above can be combined one or more activators oractivation methods described above. For example, a combination ofactivators have been described in U.S. Pat. Nos. 5,153,157 and5,453,410, European publication EP-B1 0 573 120, and PCT publications WO94/07928 and WO 95/14044. These documents all discuss the use of analumoxane and an ionizing activator with a bulky ligand metallocenecatalyst compound.

Supported Activators

Many supported activators are useful in combination with one or more ofthe polymerization catalysts, especially the bulky ligandmetallocene-type catalysts described above. A supported activator iswhere any one or more of the activators described above is supported onany one or more of the support materials described below. Non-limitingsupported activators and methods for making them are described invarious patents and publications which include: U.S. Pat. Nos.4,871,705, 4,912,075, 4,935,397, 4,937,217, 4,937,301, 5,008,228,5,015,749, 5,026,797, 5,057,475, 5,086,025, 5,147,949, 5,212,232,5,229,478, 5,288,677, 5,332,706, 5,420,220, 5,427,991, 5,446,001,5,468,702, 5,473,028, 5,534,474, 5,602,067, 5,602,217, 5,643,847,5,728,855, 5,731,451, 5,739,368, 5,756,416, 5,777,143, 5,831,109,5,856,255, 5,902,766, 5,910,463, 5,968,864 and 6,028,1516,147,173; PCTPublications Nos. WO 94/26793, WO 96/16092, WO 98/02246 and WO 99/03580;and European Publication Nos. EP-B1-0 662 979, EP 0 747 430 A1, EP 0 969019 A1, EP-B2-0 170 059, EP-A1-0 819 706 and EP-A1-0 953 581, which areall herein fully incorporated herein by reference.

Method for Supporting

The above described bulky ligand metallocene-type catalyst compounds andcatalyst systems and conventional-type transition metal catalystcompounds and catalyst systems, may be combined with one or more supportmaterials or carriers using one of the support methods well known in theart or as described below. In the preferred embodiment, thepolymerization catalyst is in a supported form. For example, in apreferred embodiment, a bulky ligand metallocene-type catalyst compoundor catalyst system is in a supported form, for example deposited on,contacted with, or incorporated within, adsorbed or absorbed in asupport or carrier.

The terms “support” or “carrier” are used interchangeably and are anyporous or non-porous support material, preferably a porous supportmaterial, for example, talc, inorganic oxides and inorganic chlorides.Other carriers include resinous support materials such as polystyrene, afunctionalized or cross linked organic supports, such as polystyrenedivinyl benzene polyolefins or polymeric compounds, or any other organicor inorganic support material and the like, or mixtures thereof.

The preferred carriers are inorganic oxides that include those Group 2,3, 4, 5, 13 or 14 metal oxides. The preferred supports includes silica,alumina, silica-alumina, magnesium chloride, and mixtures thereof. Otheruseful supports include magnesia, titania, zirconia, montmorillonite andthe like. Also, combinations of these support materials may be used, forexample, silica-chromium and silica-titania.

It is preferred that the carrier, preferably an inorganic oxide, has asurface area in the range of from about 10 to about 700 m²/g, porevolume in the range of from about 0.1 to about 4.0 cc/g and averageparticle size in the range of from about 10 to about 500 μm. Morepreferably, the surface area of the carrier is in the range of fromabout 50 to about 500 m²/g, pore volume of from about 0.5 to about 3.5cc/g and average particle size of from about 20 to about 200 μm. Mostpreferably the surface area of the carrier is in the range of from about100 to about 400 m²/g, pore volume from about 0.8 to about 3.0 cc/g andaverage particle size is from about 20 to about 100 μm. The average poresize of a carrier of the invention is typically in the range of fromabout 10 Å to 1000 Å, preferably 50 Å to about 500 Å, and mostpreferably 75 Å to about 350 Å.

Examples of supporting the bulky ligand metallocene-type catalystsystems of the invention are described in U.S. Pat. Nos. 4,701,432,4,808,561, 4,912,075, 4,925,821, 4,937,217, 5,008,228, 5,238,892,5,240,894, 5,332,706, 5,346,925, 5,422,325, 5,466,649, 5,466,766,5,468,702, 5,529,965, 5,554,704, 5,629,253, 5,639,835, 5,625,015,5,643,847, 5,648,310, 5,665,665, 5,698,487, 5,714,424, 5,723,400,5,723,402, 5,731,261, 5,743,202, 5,759,940, 5,767,032, 5,688,880,5,770,755 and 5,770,664, and U.S. application Ser. Nos. 271,598 filedJul. 7, 1994 and 788,736 filed Jan. 23, 1997 and PCT publications WO95/32995, WO 95/14044, WO 96/06187, WO96/11960 and WO96/00243, which areherein fully incorporated by reference.

Examples of supporting the conventional-type catalyst systems of theinvention are described in U.S. Pat. Nos. 4,894,424, 4,376,062,4,395,359, 4,379,759, 4,405,495 4,540,758 and 5,096,869, all of whichare herein incorporated by reference.

In one preferred embodiment, the support materials are treatedchemically, for example with a fluoride compound as described in PCTPublication No. WO 00/12565, which is herein incorporated by reference.Other supported activators are described in for example PCT PublicationNo. WO 00/13792 that refers to supported boron containing solid acidcomplex.

In one embodiment of the invention, olefin(s), preferably C₂ to C₃₀olefin(s) or alpha-olefin(s), preferably ethylene or propylene orcombinations thereof are prepolymerized in the presence of the bulkyligand metallocene-type catalyst system and/or a conventional-typetransition metal catalysts prior to the main polymerization. Theprepolymerization can be carried out batch wise or continuously in gas,solution or slurry phase including at elevated pressures. Theprepolymerization can take place with any olefin monomer or combinationand/or in the presence of any molecular weight controlling agent such ashydrogen. For examples of prepolymerization procedures, see U.S. Pat.Nos. 4,467,080, 4,748,221, 4,789,359, 4,921,825, 5,204,303, 5,283,278,5,322,830, 5,705,578, 6,391,987, 6,531,553, and 6,610,799, EuropeanPublication EP-B-0279 863 and PCT Publication No. WO 97/44371, all ofwhich are herein fully incorporated by reference. In a gas phaseprepolymerization process it is preferred to use a fluorinatedhydrocarbon as a diluent, alone or in combination with other liquids. Aprepolymerized catalyst system for purposes of this patent specificationand appended claim is a supported catalyst system.

In one embodiment the polymerization catalyst is used in an unsupportedform, preferably in a liquid form such as described in U.S. Pat. Nos.5,317,036 and 5,693,727, PCT publication WO 97/46599 and Europeanpublication EP-A-0 593 083, all of which are herein incorporated byreference.

Polymerization Process

The polymerization catalysts and catalyst systems described above aresuitable for use in any gas phase polymerization process, includingfluidized bed or stirred bed processes. Particularly preferred is a gasphase polymerization process in which one or more condensable fluids asdescribed below is utilized.

Typically in a gas phase polymerization process a continuous cycle isemployed where in one part of the cycle of a reactor system, a cyclinggas stream, otherwise known as a recycle stream or fluidizing medium, isheated in the reactor by the heat of polymerization. This heat isremoved from the recycle composition in another part of the cycle by acooling system external to the reactor. Generally, in a gas fluidizedbed process for producing polymers, a gaseous stream containing one ormore monomers is continuously cycled through a fluidized bed in thepresence of a catalyst under reactive conditions. In a preferredprocess, a condensable fluid as described below, is introduced to theprocess for purposes of increasing the cooling capacity of the recyclestream. The purposeful introduction of a condensable fluid into a gasphase process is a condensed mode process. The gaseous stream iswithdrawn from the fluidized bed and recycled back into the reactor.Simultaneously, polymer product is withdrawn from the reactor and freshmonomer is added to replace the polymerized monomer. (See for exampleU.S. Pat. Nos. 4,543,399, 4,588,790, 5,028,670, 5,317,036, 5,352,749,5,405,922, 5,436,304, 5,453,471, 5,462,999, 5,616,661 and 5,668,228 allof which are fully incorporated herein by reference.)

Condensable Fluids

There are generally two types of condensable materials employed in gasphase reactor systems, co monomers and Induced Condensing Agents (ICAs).The co monomers are typically used to control the resin product density.Common co monomers employed in gas phase reactors are 1-butene,1-hexene, and 4-methyl-1-pentene. These co monomers are consideredcondensable gases because (depending on concentration) they arerelatively easily condensed at the typical inlet gas temperatures of 30to 35° C. In contrast, ethylene, nitrogen and hydrogen in the reactionsystem are not typically condensable at these temperatures.

The second class of condensable gases in the reactor are the ICAs. Themost common type of ICA is isopentane, but isobutane, n-hexane, or otherhydrocarbons (or HFCs) of similar boiling points may also be used. Therole of the ICAs is to raise the dew point temperature of the reactorgas, so as to induce more condensing at the cooler reactor inlet gasconditions. The enhanced condensing that this provides gives additionalreactor cooling capacity and enables higher production rates from thereactor. The use of ICAs is further explained U.S. Pat. Nos. 5,352,749,5,405,922, and 5,436,304.

The condensable fluid useful in this invention are preferably inert tothe catalyst, reactants and the polymer product produced; it may alsoinclude co monomers. The condensable fluids can be introduced into thereaction/recycle system or at any other point in the system. For thepurposes of this invention and the claims thereto the term condensablefluids includes saturated or unsaturated hydrocarbons and saturated orunsaturated fluorinated hydrocarbons, including per fluorocarbons andhydro fluorocarbons. Examples of suitable inert condensable fluids arereadily volatile liquid hydrocarbons, which may be selected fromsaturated hydrocarbons containing from 2 to 10 carbon atoms, preferably3 to 10 carbon atoms. Some suitable saturated hydrocarbons are propane,n-butane, isobutane, n-pentane, isopentane, neopentane, n-hexane,isohexane, and other saturated C₆ hydrocarbons, n-heptane, n-octane andother saturated C₇ and C₈ hydrocarbons or mixtures thereof. A class ofpreferred inert condensable hydrocarbons are C₅ and C₆ saturatedhydrocarbons. Another class of preferred hydrocarbons are C₄ to C₆saturated hydrocarbons. Preferred hydrocarbons for use as condensablefluids include pentanes, such as isopentane. The condensable fluids mayalso include polymerizable condensable co monomers such as olefins,diolefins or mixtures thereof including some of the monomers mentionedherein which may be partially or entirely incorporated in the polymerproduct. Preferably, the feed or recycle stream contains from about 5 toabout 60 mole percent of a condensable fluid, preferably with thecondensable fluid having one carbon atom less than the co monomer or atleast one carbon atom less than the comonomer.

Another class of condensable fluids useful herein include fluorinatedhydrocarbons, preferably having little to no solvent power regarding thereaction components such as the monomer and polymer products. In oneembodiment, one or more fluorinated hydrocarbons or per fluorinatedcarbons are utilized as condensable fluids in the process of theinvention.

Fluorinated hydrocarbons are defined to be compounds consistingessentially of at least one carbon atom and at least one fluorine atom,and optionally at least one hydrogen atom. A per fluorinated carbon is acompound consisting essentially of carbon atom(s) and fluorine atom(s),and includes for example linear branched or cyclic, C₁ to C₄₀perfluoroalkanes, preferably Cl₁₁ to C₄₀ perfluoroalkanes. In oneembodiment, the condensable fluids, preferably the perfluorinatedcarbons exclude perfluorinated C₄₋₁₀ alkenes.

In one embodiment, the fluorinated hydrocarbons are represented by theformula:C_(x)H_(y)F_(z)  (XII)wherein x is an integer from 1 to 40, preferably from 1 to 30, morepreferably from 1 to 20, even more preferably from 1 to 10, and stilleven more preferably from 1 to 6, alternatively x is an integer from 2to 20, preferably from 3 to 10, more preferably from 3 to 6, and mostpreferably from 1 to 3, and wherein y is greater than or equal 0 and zis an integer and at least one, more preferably, y and z are integersand at least one. In a preferred embodiment, z is 2 or more.

In one embodiment, a mixture of fluorinated hydrocarbons are used as thecondensable fluids in the process of the invention, preferably a mixtureof a perfluorinated carbon and a fluorinated hydrocarbon, and morepreferably a mixture of fluorinated hydrocarbons. In yet anotherembodiment, the fluorinated hydrocarbon is balanced or unbalanced in thenumber of fluorine atoms in the fluorinated hydrocarbon compound.

Non-limiting examples of fluorinated hydrocarbons include fluoromethane;difluoromethane; trifluoromethane; fluoroethane; 1,1-difluoroethane;1,2-difluoroethane; 1,1,1-trifluoroethane; 1,1,2-trifluoroethane;1,1,1,2-tetrafluoroethane; 1,1,2,2-tetrafluoroethane;1,1,1,2,2-pentafluoroethane; 1-fluoropropane; 2-fluoropropane;1,1-difluoropropane; 1,2-difluoropropane; 1,3-difluoropropane;2,2-difluoropropane; 1,1,1-trifluoropropane; 1,1,2-trifluoropropane;1,1,3-trifluoropropane; 1,2,2-trifluoropropane; 1,2,3-trifluoropropane;1,1,1,2-tetrafluoropropane; 1,1,1,3-tetrafluoropropane;1,1,2,2-tetrafluoropropane; 1,1,2,3-tetrafluoropropane;1,1,3,3-tetrafluoropropane; 1,2,2,3-tetrafluoropropane;1,1,1,2,2-pentafluoropropane; 1,1,1,2,3-pentafluoropropane;1,1,1,3,3-pentafluoropropane; 1,1,2,2,3-pentafluoropropane;1,1,2,3,3-pentafluoropropane; 1,1,1,2,2,3-hexafluoropropane;1,1,1,2,3,3-hexafluoropropane; 1,1,1,3,3,3-hexafluoropropane;1,1,1,2,2,3,3-heptafluoropropane; 1,1,1,2,3,3,3-heptafluoropropane;1-fluorobutane; 2-fluorobutane; 1,1-difluorobutane; 1,2-difluorobutane;1,3-difluorobutane; 1,4-difluorobutane; 2,2-difluorobutane;2,3-difluorobutane; 1,1,1-trifluorobutane; 1,1,2-trifluorobutane;1,1,3-trifluorobutane; 1,1,4-trifluorobutane; 1,2,2-trifluorobutane;1,2,3-trifluorobutane; 1,3,3-trifluorobutane; 2,2,3-trifluorobutane;1,1,1,2-tetrafluorobutane; 1,1,1,3-tetrafluorobutane;1,1,1,4-tetrafluorobutane; 1,1,2,2-tetrafluorobutane;1,1,2,3-tetrafluorobutane; 1,1,2,4-tetrafluorobutane;1,1,3,3-tetrafluorobutane; 1,1,3,4-tetrafluorobutane;1,1,4,4-tetrafluorobutane; 1,2,2,3-tetrafluorobutane;1,2,2,4-tetrafluorobutane; 1,2,3,3-tetrafluorobutane;1,2,3,4-tetrafluorobutane; 2,2,3,3-tetrafluorobutane;1,1,1,2,2-pentafluorobutane; 1,1,1,2,3-pentafluorobutane;1,1,1,2,4-pentafluorobutane; 1,1,1,3,3-pentafluorobutane;1,1,1,3,4-pentafluorobutane; 1,1,1,4,4-pentafluorobutane;1,1,2,2,3-pentafluorobutane; 1,1,2,2,4-pentafluorobutane;1,1,2,3,3-pentafluorobutane; 1,1,2,4,4-pentafluorobutane;1,1,3,3,4-pentafluorobutane; 1,2,2,3,3-pentafluorobutane;1,2,2,3,4-pentafluorobutane; 1,1,1,2,2,3-hexafluorobutane;1,1,1,2,2,4-hexafluorobutane; 1,1,1,2,3,3-hexafluorobutane,1,1,1,2,3,4-hexafluorobutane; 1,1,1,2,4,4-hexafluorobutane;1,1,1,3,3,4-hexafluorobutane; 1,1,1,3,4,4-hexafluorobutane;1,1,1,4,4,4-hexafluorobutane; 1,1,2,2,3,3-hexafluorobutane;1,1,2,2,3,4-hexafluorobutane; 1,1,2,2,4,4-hexafluorobutane;1,1,2,3,3,4-hexafluorobutane; 1,1,2,3,4,4-hexafluorobutane;1,2,2,3,3,4-hexafluorobutane; 1,1,1,2,2,3,3-heptafluorobutane;1,1,1,2,2,4,4-heptafluorobutane; 1,1,1,2,2,3,4-heptafluorobutane;1,1,1,2,3,3,4-heptafluorobutane; 1,1,1,2,3,4,4-heptafluorobutane;1,1,1,2,4,4,4-heptafluorobutane; 1,1,1,3,3,4,4-heptafluorobutane;1,1,1,2,2,3,3,4-octafluorobutane; 1,1,1,2,2,3,4,4-octafluorobutane;1,1,1,2,3,3,4,4-octafluorobutane; 1,1,1,2,2,4,4,4-octafluorobutane;1,1,1,2,3,4,4,4-octafluorobutane; 1,1,1,2,2,3,3,4,4-nonafluorobutane;1,1,1,2,2,3,4,4,4-nonafluorobutane; 1-fluoro-2-methylpropane;1,1-difluoro-2-methylpropane; 1,3-difluoro-2-methylpropane;1,1,1-trifluoro-2-methylpropane; 1,1,3-trifluoro-2-methylpropane;1,3-difluoro-2-(fluoromethyl)propane;1,1,1,3-tetrafluoro-2-methylpropane;1,1,3,3-tetrafluoro-2-methylpropane;1,1,3-trifluoro-2-(fluoromethyl)propane;1,1,1,3,3-pentafluoro-2-methylpropane;1,1,3,3-tetrafluoro-2-(fluoromethyl)propane;1,1,1,3-tetrafluoro-2-(fluoromethyl)propane; fluorocyclobutane;1,1-difluorocyclobutane; 1,2-difluorocyclobutane;1,3-difluorocyclobutane; 1,1,2-trifluorocyclobutane;1,1,3-trifluorocyclobutane; 1,2,3-trifluorocyclobutane;1,1,2,2-tetrafluorocyclobutane; 1,1,3,3-tetrafluorocyclobutane;1,1,2,2,3-pentafluorocyclobutane; 1,1,2,3,3-pentafluorocyclobutane;1,1,2,2,3,3-hexafluorocyclobutane; 1,1,2,2,3,4-hexafluorocyclobutane;1,1,2,3,3,4-hexafluorocyclobutane; 1,1,2,2,3,3,4-heptafluorocyclobutane.Particularly preferred fluorinated hydrocarbons include difluoromethane,trifluoromethane, 1,1-difluoroethane, 1,1,1-trifluoroethane,fluoromethane, and 1,1,1,2-tetrafluoroethane. In addition to thosefluorinated hydrocarbons described herein, those fluorinatedhydrocarbons described in Raymond Will, et. al., CEH Marketing Report,Fluorocarbons, Pages 1-133, by the Chemical Economics Handbook-SRIInternational, April 2001, which is fully incorporated herein byreference, are included.

In another embodiment the condensable fluids, such as fluorinatedhydrocarbons, are used in combination with one or more inert gases suchas carbon dioxide, nitrogen, hydrogen, argon, neon, helium, krypton,xenon, and the like. In the preferred embodiment, the inert gas isnitrogen.

In another preferred embodiment, the fluorinated hydrocarbon used in theprocess of the invention are selected from the group consisting ofdifluoromethane, trifluoromethane, 1,1-difluoroethane,1,1,1-trifluoroethane, and 1,1,1,2-tetrafluoroethane and mixturesthereof.

In one particularly preferred embodiment, the commercially availablefluorinated hydrocarbons useful in the process of the invention includeHFC-236fa having the chemical name 1,1,1,3,3,3-hexafluoropropane,HFC-134a having the chemical name 1,1,1,2-tetrafluoroethane, HFC-245fahaving the chemical name 1,1,1,3,3-pentafluoropropane, HFC-365mfc havingthe chemical name 1,1,1,3,3-pentafluorobutane, R-318 having the chemicalname octafluorocyclobutane, and HFC-43-10mee having the chemical name2,3-dihydrodecafluoropentane and/or HFC-365mfc, all of these arecommercially available fluorinated hydrocarbons.

In another embodiment, the condensable fluid is not a perfluorinated C4to C10 alkane. In another embodiment, the condensable fluid is not aperfluorinated hydrocarbon. In another embodiment, the condensable fluidis not perfluorodecalin, perfluoroheptane, perfluorohexane,perfluoromethylcyclohexane, perfluorooctane,perfluoro-1,3-dimethylcyclohexane, perfluorononane, fluorobenzene, orperfluorotoluene. In a particularly preferred embodiment, thefluorocarbon consists essentially of hydro fluorocarbons. In aparticularly preferred embodiment, the condensable fluid consistsessentially of hydro fluorocarbons.

In another embodiment the fluorocarbon is present at more than 1 weight%, based upon the weight of the condensable fluid (fluorocarbon and anyhydrocarbon solvent) present in the reactor, preferably greater than 3weight %, preferably greater than 5 weight %, preferably greater than 7weight %, preferably greater than 10 weight %, preferably greater than15 weight %, preferably greater than 20 weight %, preferably greaterthan 25 weight %, preferably greater than 30 weight %, preferablygreater than 35 weight %, preferably greater than 40 weight %,preferably greater than 50 weight %, preferably greater than 55 weight%, preferably greater than 60 weight %, preferably greater than 70weight %, preferably greater than 80 weight %, preferably greater than90 weight %. In another embodiment the fluorocarbon is present at morethan 1 weight %, based upon the weight of the fluorocarbons, monomersand any hydrocarbon solvent present in the reactor, preferably greaterthan 3 weight %, preferably greater than 5 weight %, preferably greaterthan 7 weight %, preferably greater than 10 weight %, preferably greaterthan 15 weight %, preferably greater than 20 weight %, preferablygreater than 25 weight %, preferably greater than 30 weight %,preferably greater than 35 weight %, preferably greater than 40 weight%, preferably greater than 50 weight %, preferably greater than 55weight %, preferably greater than 60 weight %, preferably greater than70 weight %, preferably greater than 80 weight %, preferably greaterthan 90 weight %. In the event that the weight basis is not named forthe weight % fluorocarbon, it shall be presumed to be based upon thetotal weight of the fluorocarbons, monomers and hydrocarbon solventspresent in the reactor.

In another embodiment the fluorocarbon, preferably thehydrofluorocarbon, is present at more than 1 volume %, based upon thetotal volume of the fluorocarbon, monomers and any hydrocarbon solventpresent in the reactor, preferably greater than 3 volume %, preferablygreater than 5 volume %, preferably greater than 7 volume %, preferablygreater than 10 volume %, preferably greater than 15 volume %,preferably greater than 20 volume %, preferably greater than 25 volume%, preferably greater than 30 volume %, preferably greater than 35volume %, preferably greater than 40 volume %, preferably greater than45 volume %, preferably greater than 50 volume %, preferably greaterthan 55 volume %, preferably greater than 60 volume %, preferablygreater than 65 volume %.

In yet another embodiment, the fluorinated hydrocarbons useful hereinhave a molecular weight (MW) greater than 90 a.m.u., preferably greaterthan 95 a.m.u, and more preferably greater than 100 a.m.u. In anotherembodiment, the fluorinated hydrocarbons useful herein have a MW greaterthan 120 a.m.u, preferably greater than 125 a.m.u, even more preferablygreater than 130 a.m.u, and most preferably greater than 140 a.m.u. Instill another embodiment, the fluorinated hydrocarbons useful hereinhave a MW greater than 125 a.m.u, preferably greater than 130 a.m.u,even more preferably greater than 135 a.m.u, and most preferably greaterthan 150 a.m.u. In another embodiment, the fluorinated hydrocarbonsuseful herein have a MW greater than 140 a.m.u, preferably greater than150 a.m.u, more preferably greater than 180 a.m.u, even more preferablygreater than 200 a.m.u, and most preferably greater than 225 a.m.u. Inan embodiment, the fluorinated hydrocarbons useful herein have a MW inthe range of from 90 a.m.u to 1000 a.m.u, preferably in the range offrom 100 a.m.u to 500 a.m.u, more preferably in the range of from 100a.m.u to 300 a.m.u, and most preferably in the range of from about 100a.m.u to about 250 a.m.u.

In yet another embodiment, the fluorinated hydrocarbons useful hereinhave normal boiling points in the range of from about −50° C. up to thepolymerization temperature, preferably a polymerization temperature ofabout 85° C., preferably the normal boiling points of the fluorinatedhydrocarbons are in the range of from −40° C. to about 70° C., morepreferably from about −30° C. to about 60° C., and most preferably fromabout −30° C. to about 55° C. In an embodiment, the fluorinatedhydrocarbons useful herein have normal boiling points greater than −30°C., preferably greater than −30° C. to less than −10° C. In a furtherembodiment, the fluorinated hydrocarbons useful herein have normalboiling points greater than −5° C., preferably greater than −5° C. toless than −20° C. In one embodiment, the fluorinated hydrocarbons usefulherein have normal boiling points greater than 30° C., preferablygreater than 30° C. to about 60° C.

In another embodiment, the fluorinated hydrocarbons useful herein have aliquid density at 20° C. (g/cc) greater than 1 g/cc, preferably greaterthan 1.10, and most preferably greater than 1.20 g/cc. In oneembodiment, the fluorinated hydrocarbons useful herein have a liquiddensity at 20° C. (g/cc) greater than 1.20 g/cc, preferably greater than1.25, and most preferably greater than 1.30 g/cc. In an embodiment, thefluorinated hydrocarbons useful herein have a liquid density at 20° C.(g/cc) greater than 1.30 g/cc, preferably greater than 1.40, and mostpreferably greater than 1.50 g/cc.

In one embodiment, the fluorinated hydrocarbons useful herein have aHeat of Vaporization (ΔH Vaporization) as measured by standardcalorimetric techniques in the range between 100 kJ/kg to less than 300kJ/kg, preferably in the range of from 110 kJ/kg to less than 300 kJ/kg,and most preferably in the range of from 120 kJ/kg to less than 300kJ/kg.

In another preferred embodiment, the fluorinated hydrocarbons usefulherein have any combination of two or more of the aforementioned MW,normal boiling point, ΔH Vaporization, and liquid density values andranges. In a preferred embodiment, the fluorinated hydrocarbons usefulin the process of the invention have a MW greater than 90 a.m.u,preferably greater than 100 a.m.u, and a liquid density greater than1.00 g/cc, preferably greater than 1.20 g/cc. In yet another preferredembodiment, the fluorinated hydrocarbons useful in the process of theinvention have a liquid density greater than 1.10 g/cc, preferablygreater than 1.20 g/cc, and a normal boiling point greater than −50° C.,preferably greater than −30° C. up to the polymerization temperature ofthe process, which is as high as 100° C., preferably less than 85° C.,and more preferably less than 75° C., and most preferably less than 60°C. In one embodiment, the fluorinated hydrocarbons useful in the processof the invention have a MW greater than 90 a.m.u, preferably greaterthan 100 a.m.u, and a ΔH Vaporization in the range of from 100 kj/kg toless than 300 kj/kg, and optionally a liquid density greater than 1.00g/cc, preferably greater than 1.20 g/cc. In yet another embodiment, thefluorinated hydrocarbons useful in the process of the invention have aliquid density greater than 1.10 g/cc, preferably greater than 1.20g/cc, and a normal boiling point greater than −50° C., preferablygreater than −30° C. up to the polymerization temperature of theprocess, which is as high as 100° C., preferably less than 85° C., andmore preferably less than 75° C., and most preferably less than 60° C.,and optionally a ΔH Vaporization in the range of from 120 kj/kg to lessthan 250 kj/kg.

In yet another embodiment, one or more fluorinated hydrocarbon(s), aloneor in combination, with one or more inert, readily volatile liquidhydrocarbons, which include, for example, saturated hydrocarbonscontaining from 3 to 8 carbon atoms, such as propane, n-butane,isobutane (MW of 58.12 a.m.u, a liquid density of 0.55 g/cc, and normalboiling point as above described of −11.75), n-pentane, isopentane (MWof 72.15 a.m.u, a liquid density of 0.62 g/cc, and normal boiling pointof 27.85), neopentane, n-hexane, isohexane, and other saturated C₆ to C₈hydrocarbons.

In another embodiment, the fluorinated hydrocarbon(s) is selected basedupon its solubility or lack thereof in a particular polymer beingproduced. Preferred fluorinated hydrocarbon(s) have little to nosolubility in the polymer. Solubility in the polymer is measured byforming the polymer into a film of thickness between 50 and 100 microns,then soaking it in diluent (enough to cover the film) for 4 hours at therelevant desired temperature in a sealed container or vessel. The filmis removed from the fluorinated hydrocarbon(s), exposed for 90 secondsto evaporate excess condensable fluid from the surface of the film, andweighed. The mass uptake is defined as the percentage increase in thefilm weight after soaking. The fluorinated hydrocarbon or fluorinatedhydrocarbon mixture is selected so that the polymer has a mass uptake ofless than 4 wt %, preferably less than 3 wt %, more preferably less than2 wt %, even more preferably less than 1 wt %, and most preferably lessthan 0.5 wt %.

Ideally, the fluorocarbon is inert to the polymerization reaction. By“inert to the polymerization reaction” is meant that the fluorocarbondoes not react chemically with the, monomers, catalyst system or thecatalyst system components. (This is not to say that the physicalenvironment provided by an FC's does not influence the polymerizationreactions, in fact, it may do so to some extent, such as affectingactivity rates. However, it is meant to say that the FC's are notpresent as part of the catalyst system.)

In a preferred embodiment, the fluorinated hydrocarbon(s) or mixturesthereof, are selected such that the polymer melting temperature Tm isreduced (or depressed) by not more than 15° C. by the presence of thecondensable fluid. The depression of the polymer melting temperature ΔTmis determined by first measuring the melting temperature of a purepolymer (Tm) by differential scanning calorimetric (DSC), and thencomparing this to a similar measurement on a sample of the same polymerthat has been soaked with the condensable fluid. In general, the meltingtemperature of the soaked polymer will be lower than or equal to that ofthe dry polymer. The difference in these measurements is taken as themelting point depression ΔTm. It is well known to those in the art thathigher concentrations of dissolved materials in the polymer cause largerdepressions in the polymer melting temperature (i.e. higher values ofΔTm). A suitable DSC technique for determining the melting pointdepression is described by, P. V. Hemmingsen, “Phase Equilibria inPolyethylene Systems”, Ph.D Thesis, Norwegian University of Science andTechnology, March 2000, which is incorporated herein by reference. (Apreferred set of conditions for conducting the tests are summarized onPage 112 of this reference.) The polymer melting temperature is firstmeasured with dry polymer, and then repeated with the polymer immersedin liquid (the condensable fluid to be evaluated). As described in thereference above, it is important to ensure that the second part of thetest, conducted in the presence of the liquid, is done in a sealedcontainer so that the liquid is not flashed during the test, which couldintroduce experimental error.

In one embodiment, the ΔTm of polymers in the presence of thecondensable fluid, especially the polymers made in the presence offluorinated hydrocarbon, is less than 12° C., preferably less than 10°C., preferably less than 8° C., more preferably less than 6° C., andmost preferably less than 4° C. below the pure polymer Tm, as definedabove. In another embodiment, the measured ΔTm is less than 5° C.,preferably less than 4° C., more preferably less than 3° C., even morepreferably less than 2° C., and most preferably less than 1° C. than thepure polymer Tm as measured above.

Monomers

Polymers produced according to this invention are olefin polymers or“polyolefins”. By olefin polymers is meant that at least 75 mole % ofthe polymer is made of hydrocarbon monomers, preferably at least 80 mole%, preferably at least 85 mole %, preferably at least 90 mole %,preferably at least 95 mole %, preferably at least 99 mole %. In aparticularly preferred embodiment, the polymers are 100 mole %hydrocarbon monomer. Hydrocarbon monomers are monomers made up of onlycarbon and hydrogen. In another embodiment of the invention up to 25 mol% of the polyolefin is derived from heteroatom containing monomers.Heteroatom containing monomers are hydrocarbon monomers where one ormore hydrogen atoms have been replaced by a heteroatom. In a preferredembodiment, the heteroatom is selected from the group consisting ofchlorine, bromine, oxygen, nitrogen, silicon and sulfur, preferably theheteroatom is selected from the group consisting of oxygen, nitrogen,silicon and sulfur, preferably the heteroatom is selected from the groupconsisting of oxygen and nitrogen, preferably oxygen. In a preferredembodiment, the heteroatom is not fluorine. In another embodiment of theinvention, the monomers to be polymerized are not fluormonomers.Fluoromonomers are defined to be hydrocarbon monomers where at least onehydrogen atom has been replaced by a fluorine atom. In anotherembodiment of the invention, the monomers to be polymerized are not halomonomers. (By halo monomer is meant a hydrocarbon monomer where at leastone hydrogen atom is replaced by a halogen.) In another embodiment ofthe invention, the monomers to be polymerized are not vinyl aromatichydrocarbons. In another embodiment of the invention, the monomers to bepolymerized are preferably aliphatic or alicyclic hydrocarbons. (asdefined under “Hydrocarbon” in Hawley's Condensed Chemical Dictionary,13th edition, R. J. Lewis ed., John Wiley and Sons, New York, 1997. Inanother embodiment of the invention, the monomers to be polymerized arepreferably linear or branched alpha-olefins, preferably C2 to C40 linearor branched alpha-olefins, preferably C2 to C20 linear or branchedalpha-olefins, preferably ethylene, propylene, butene, pentene, hexene,heptene, octene, nonene, decene, undecene, dodecene, or mixturesthereof, more preferably ethylene, propylene, butene hexene and octene.

In one embodiment, the process of this invention is directed toward agas phase polymerization process of one or more olefin monomers havingfrom 2 to 30 carbon atoms, preferably 2 to 12 carbon atoms, and morepreferably 2 to 8 carbon atoms. The invention is particularly wellsuited to the polymerization of two or more olefin monomers of ethylene,propylene, butene-1, pentene-1,4-methyl-pentene-1, hexene-1, octene-1and decene-1.

Other monomers useful in the process of the invention includeethylenically unsaturated monomers, diolefins having 4 to 18 carbonatoms, conjugated or nonconjugated dienes, polyenes, vinyl monomers andcyclic olefins. Non-limiting monomers useful in the invention includebutadiene, norbornene, norbornadiene, isobutylene,vinylbenzocyclobutane, ethylidene norbornene, isoprene,dicyclopentadiene and cyclopentene.

In a preferred embodiment of the process of the invention, a copolymerof ethylene is produced, where the ethylene and a comonomer having atleast one alpha-olefin having from 3 to 15 carbon atoms, preferably from4 to 12 carbon atoms, and most preferably from 4 to 8 carbon atoms, arepolymerized in a gas phase process.

In another embodiment of the process of the invention, ethylene orpropylene is polymerized with at least two different comonomers,optionally one of which may be a diene, to form a terpolymer.

Condensed Mode Process

In a preferred gas phase process of the invention, the gas phase processis operated in a condensed mode, where an inert condensable fluid asdescribed above, especially a C₂ to C₁₀ saturated hydrocarbon and/or afluorinated hydrocarbon, is introduced to the process to increase thecooling capacity of the recycle stream. These inert condensable fluidsare referred to as induced condensing agents or ICA's. In anotherembodiment the invention relates to a gas phase process for polymerizingone or more olefin(s), preferably at least one of which is ethylene orpropylene, in a fluidized bed reactor, the process operating in acondensed mode in which a liquid and a gas are introduced to thefluidized bed reactor having a fluidizing medium or a stirred bedreactor having a medium, wherein the level of condensable fluid isgreater than 5 weight percent, preferably greater than 10 weightpercent, or greater than 15 weight percent or greater than 20 weightpercent, more preferably greater than 25 weight percent, even morepreferably greater than 30 weight percent, still even more preferablygreater than 35 weight percent, and most preferably greater than 30weight percent up to 60 weight percent, preferably 50 weight percent,based on the total weight of the liquid and gas entering the reactor.For further details of a condensed mode process see U.S. Pat. Nos.5,342,749 and 5,436,304 both of which are herein fully incorporatedherein by reference.

To achieve higher cooling capacities, and enable higher reactorproduction rates, it is desirable to raise the dew point temperature ofthe recycle stream to permit a higher level of condensing at the inletto the gas phase reactor. The dew point temperature of the recyclestream is typically raised by increasing the operating pressure of thereaction/recycle system and/or increasing the percentage of condensablefluids (ICA's and/or comonomers) and decreasing the percentage ofnon-condensable gases in the recycle stream. The advantages of a processoperating in condensed mode generally increase directly with thenearness of the dew point temperature of the recycle steam to thereaction temperature within the interior of the fluidized bed. Theadvantages of the process may increase directly with the percentage ofliquid in the recycle stream returned to the reactor. For a given inletgas temperature, higher dew point temperatures cause an increased levelof condensing (higher weight percent condensed). The higher condensinglevels provide additional cooling and hence higher production ratecapability in the reactor.

In one preferred embodiment of the invention, the invention is directedto a process, preferably a continuous process, for polymerizingmonomer(s) in a reactor, said process comprising the steps of: (a)introducing a recycle stream into the reactor (optionally an insulatedreactor), the recycle stream comprising one or more monomer(s); (b)introducing a polymerization catalyst and a condensable fluid,preferably a C2 to C10 saturated hydrocarbon and/or a fluorinatedhydrocarbon, into the reactor where the reactor temperature is below theCritical Temperature, optionally for more than 12 hours; (c) withdrawingthe recycle stream from the reactor; (d) cooling the recycle stream toform a gas phase and a liquid phase; (e) reintroducing the gas phase andthe liquid phase into the reactor; (f) introducing into the reactoradditional monomer(s) to replace the monomer(s) polymerized; and (g)withdrawing a polymer product from the reactor. In a most preferredembodiment, the condensable fluid is introduced in amount greater than 5weight percent or greater than 10 weight percent or greater than 15weight percent or greater than 20 weight percent, preferably greaterthan 25 weight percent, more preferably greater than 30 weight percent,and most preferably greater than 40 weight percent based on the totalweight of fluidizing medium being reintroduced into the reactor.

In another preferred embodiment of the invention, the invention isdirected to a process, preferably a continuous process, for polymerizingmonomer(s) in a reactor, said process comprising the steps of: (a)introducing a recycle stream into the reactor (optionally an insulatedreactor), the recycle stream comprising one or more monomer(s); (b)introducing a polymerization catalyst and a condensable fluid,preferably a C2 to C10 hydrocarbon and/or a fluorinated hydrocarbon,into the reactor where the reactor bed temperature is below the CriticalTemperature and preferably the dew point temperature is within 25° C. ofthe bed temperature, optionally for more than 12 hours; (c) withdrawingthe recycle stream from the reactor; (d) cooling the recycle stream toform a gas phase and a liquid phase; (e) reintroducing the gas phase andthe liquid phase into the reactor; (f) introducing into the reactoradditional monomer(s) to replace the monomer(s) polymerized; and (g)withdrawing a polymer product from the reactor. In this embodiment, thecondensable fluid is introduced in a concentration greater than 0.5 molepercent, preferably greater than 1 mole percent, preferably greater than2 mole percent, more preferably greater than 3 mole percent, even morepreferably greater than 4 mole percent, still even more preferablygreater than 5 mole percent, and most preferably greater than 7 molepercent, based on the total moles of gas in the reactor.

Other gas phase processes in which can be practiced below the Criticaltemperature with or without an insulated reactor include those describedin U.S. Pat. Nos. 5,627,242, 5,665,818 and 5,677,375, and Europeanpublications EP-A-0 794 200, EP-A-0 802 202, EP-A2 0 891 990 andEP-B-634 421, all of which are herein fully incorporated by reference.

Reactor Conditions

The reactor pressure in any of the gas phase processes described in theabove embodiments vary from about 100 psig (690 kPa) to about 500 psig(3448 kPa), preferably in the range of from about 200 psig (1379 kPa) toabout 400 psig (2759 kPa), more preferably in the range of from about250 psig (1724 kPa) to about 350 psig (2414 kPa).

The reactor bed temperature in any of the gas phase processes describedin the above embodiments may vary from about 30° C. to about 120° C.,preferably from about 60° C. to about 115° C., more preferably in therange of from about 70° C. to 110° C., and most preferably in the rangeof from about 70° C. to about 100° C. In another embodiment, the bedtemperature is above room temperature (23° C.), preferably above 30° C.,preferably above 50° C., preferably above 70° C.

In a preferred embodiment, in any of the gas phase processes describedin the above embodiments, the process is producing greater than 500 lbsof polymer per hour (227 Kg/hr) to about 200,000 lbs/hr (90,900 Kg/hr)or higher of polymer, preferably greater than 1000 lbs/hr (455 Kg/hr),more preferably greater than 10,000 lbs/hr (4540 Kg/hr), even morepreferably greater than 25,000 lbs/hr (11,300 Kg/hr), still morepreferably greater than 35,000 lbs/hr (15,900 Kg/hr), still even morepreferably greater than 50,000 lbs/hr (22,700 Kg/hr), and mostpreferably greater than 65,000 lbs/hr (29,000 Kg/hr) to greater than100,000 lbs/hr (45,500 Kg/hr)

In a preferred embodiment of the process of invention in any of theembodiments described herein, the condensable fluid is used in an amountsuch that the molar ratio of the condensable fluid(s) to the metal ofone or more of the polymerization catalyst(s) or catalyst system(s),especially where the metal is from a Group 3 though 12 metal, preferablya Group 3 through 8 metal, and most preferably a Group 4 through 6metal, is in the molar ratio of from 500:1 to 20,000:1, preferably from500:1 to 10,000:1, preferably from 900:1 to 8000:1, even more preferablyfrom 2000:1 to 5000:1, and most preferably from to 2000:1 to 3500:1. Inanother preferred embodiment of the process of invention in any of theembodiments described herein, the fluorinated hydrocarbon is used in anamount such that the molar ratio of the one or more fluorinatedhydrocarbon(s) to the metal of one or more of the polymerizationcatalyst(s) or catalyst system(s), especially where the metal is from aGroup 3 though 12 metal, preferably a Group 3 through 8 metal, and mostpreferably a Group 4 through 6 metal, is in the molar ratio greater than500:1, preferably greater than from 900:1, even more preferably greaterthan 1000:1, still even more preferably greater than 2000:1, still evenmore preferably greater than 3000:1, still even more preferably greaterthan 10,000:1, and most preferably greater than 20,000:1. In the aboveembodiments, the most preferable metals are the transition metals,preferably Group 4 through 6 transition metals including titanium,hafnium, zirconium, chromium and vanadium.

In another preferred embodiment of any of the embodiments of the processof invention herein, the amount of one or more condensable fluids isdetermined by the partial pressure of the one or more fluorinatedhydrocarbon(s) being introduced to the process, particularly into thereactor. In this embodiment, the partial pressure of the condensablefluid (preferably a C2 to C10 saturated hydrocarbon and/or one or morefluorinated hydrocarbons) is in the range of from 1 psia (6.9 kPa) to500 psia (3448 kPa), preferably is in the range from about 2 psig (13.8kPa) to about 250 psia (1724 kPa), more preferably is in the range from2 psia (13.8 kPa) to 100 psia (690 kPa), still more preferably in therange from about 5 psia (34.5 kPa) to 90 psia (621 kPa), and mostpreferably in the range of from 5 psia (34.5 kPa) to about 80 psia (552kPa).

In any of the embodiments described herein, the fluorinated hydrocarbonis present at 5 mole % or more, based upon the moles of fluorinatedhydrocarbon, hydrocarbon solvent and monomers present in the reactor,alternately at 10 mole % or more, alternately at 15 mole % or more,alternately at 20 mole % or more, alternately at 25 mole % or more,alternately at 30 mole % or more, alternately at 35 mole % or more,alternately at 40 mole % or more, alternately at 45 mole % or more,alternately at 50 mole % or more, alternately at 55 mole % or more,alternately at 60 mole % or more, alternately at 65 mole % or more.

Polymer Product of the Invention

The polymers produced by the process of the invention are useful inmaking a wide variety of products and useful in many end-useapplications. The polymers produced by the process of the inventioninclude linear low density polyethylenes, elastomers, plastomers, highdensity polyethylenes, low density polyethylenes, polypropylene andpolypropylene copolymers.

The polymers produced, typically ethylene based polymers, have a densityin the range of from 0.86 g/cc to 0.97 g/cc, preferably in the range offrom 0.88 g/cc to 0.965 g/cc, more preferably in the range of from 0.900g/cc to 0.96 g/cc, even more preferably in the range of from 0.905 g/ccto 0.95 g/cc, yet even more preferably in the range from 0.910 g/cc to0.940 g/cc, and most preferably greater than 0.915 g/cc.

In one embodiment, the polymers produced by the process of the inventiontypically have a molecular weight distribution, a weight averagemolecular weight to number average molecular weight (M_(w)/M_(n)) ofgreater than 1.5 to about 30, particularly greater than 2 to about 15,more preferably greater than 2 to about 10, even more preferably greaterthan about 2.2 to less than about 8, and most preferably from 2.5 to 8.The ratio of M_(w)/M_(n) is measured by gel permeation chromatographytechniques well known in the art.

In yet another embodiment, the ethylene-based polymers produced by theprocess of the invention typically have a narrow or broad compositiondistribution as measured by Composition Distribution Breadth Index(CDBI). Further details of determining the CDBI of a copolymer are knownto those skilled in the art. See, for example, PCT Patent Application WO93/03093, published Feb. 18, 1993, which is fully incorporated herein byreference. Typically when a bulky ligand metallocene-type polymerizationcatalyst is utilized in the process of the invention producing anethylene copolymer, terpolymer and the like, the CDBI's are generally inthe range of greater than 50% to 99%, preferably in the range of 55% to85%, and more preferably 60% to 80%, even more preferably greater than60%, still even more preferably greater than 65%. Typically when aconventional-type transition metal polymerization catalyst is utilizedin the process of the invention producing an ethylene copolymer,terpolymer and the like, the CDBI's are generally less than 50%, morepreferably less than 40%, and most preferably less than 30%. Also,whether a bulky ligand metallocene-type polymerization catalyst or aconventional-type transition metal polymerization catalyst is being usedand the process is making an ethylene homopolymer, the CDBI is 100%.

Generally, the polymers produced by the process of the invention in oneembodiment have a melt index (MI) or (I₂) as measured by ASTM-D-1238-Ein the range from 0.01 dg/min to 1000 dg/min, more preferably from about0.01 dg/min to about 100 dg/min, even more preferably from about 0.1dg/min to about 50 dg/min, and most preferably from about 0.1 dg/min toabout 10 dg/min. Also, generally, the polymers of the invention in anembodiment have a melt index ratio (I₂₁/I₂) (I₂₁ is measured byASTM-D-1238-F) of from 10 to less than 25, more preferably from about 15to less than 25. Further, in another embodiment, the polymers have amelt index ratio (I₂₁/I₂) (I₂₁ is measured by ASTM-D-1238-F) of frompreferably greater than 25, more preferably greater than 30, even morepreferably greater that 40, still even more preferably greater than 50and most preferably greater than 65. In yet another embodiment, thepolymers, particularly polymers produced in the process of the inventionusing a Ziegler-Natta-type polymerization catalyst, have a melt indexratio (I₂₁/I₂) (I₂₁ is measured by ASTM-D-1238-F) in the range of from15 to 40, preferably in the range of from about 20 to about 35, morepreferably in the range of from about 22 to about 30, and mostpreferably in the range of from 24 to 27.

In yet another embodiment, propylene based polymers are produced in theprocess of the invention. These polymers include atactic polypropylene,isotactic polypropylene, and syndiotactic polypropylene. Other propylenepolymers include propylene random, block or impact copolymers.

In one embodiment, the invention is directed to a gas phase process forpolymerizing one or more monomer(s) producing a polymer product in thepresence of a catalyst system and a condensable fluid (preferably a C2to C10 saturated hydrocarbon and/or a fluorinated hydrocarbon) at atemperature below the Critical Temperature, optionally in an insulatedreactor, optionally for a period of 12 hours or more, wherein thecatalyst system is a bulky ligand metallocene-type catalyst systems aspreviously defined, and the polymer product having a density (asmeasured by ASTM D 1238) in the range of from about 0.915 g/cc to about0.950 g/cc, preferably in the range of from about 0.915 g/cc to 0.945g/cc, and more preferably in the range of from about 0.915 g/cc to about0.940 g/cc, and a polymer production rate greater than 40,000 kg/hour,preferably greater than 55,000 kg/hour and most preferably greater than70,000 kg/hour. In a preferred embodiment, the gas phase processincludes a fluidizing medium that is introduced to a reactor, and theprocess is operating in a condensed mode wherein the level of condensingor condensed liquid is greater than 15 weight percent, preferablygreater than 32 weight percent, and most preferably greater than 50weight percent based on the total weight of fluidizing medium beingintroduced into the reactor. In yet another embodiment, the partialpressure of the condensable fluid (preferably a C2 to C10 saturatedhydrocarbon and/or a fluorinated hydrocarbon) is in the range of from 30psia (207 kpa) to about 100 psia (690 kPa), preferably in the range fromabout 35 psia (241 kPa) to 90 psia (621 kPa), and most preferably in therange of from 40 psia (276 kPa) to about 80 psia (552 kPa).

In one embodiment, the invention is directed to a gas phase process forpolymerizing one or more hydrocarbon monomer(s) producing a polymerproduct in the presence of a catalyst system (at a temperature below theCritical Temperature optionally in an insulated reactor and optionallyfor a period of 12 hours or more) and a condensable fluid (preferably aC2 to C10 saturated hydrocarbon and/or a fluorinated hydrocarbon),wherein the catalyst system is a bulky ligand metallocene-type catalystsystems as previously defined, and the polymer product having a densityin the range of from about 0.87 g/cc to less than 0.915 g/cc, preferablyin the range of from about 0.88 g/cc to 0.914 g/cc, and more preferablyin the range of from about 0.900 g/cc to 0.913 g/cc, and a polymerproduction rate greater than 35,000 kg/hour, preferably greater than50,000 kg/hour and most preferably greater than 65,000 kg/hour. In apreferred embodiment, the gas phase process includes a fluidizing mediumthat is introduced to a reactor, and the process is operating in acondensed mode wherein the level of condensing or condensed is greaterthan 15 weight percent, preferably greater than 32 weight percent, andmost preferably greater than 50 weight percent based on the total weightof fluidizing medium being introduced into the reactor. In yet anotherembodiment, the partial pressure of the fluorinated hydrocarbon is inthe range of from 10 psia (69 kPa) to about 100 psia (690 kPa),preferably in the range from about 15 psia (103 kPa) to 90 psia (621kPa), and most preferably in the range of from 20 psia (138 kPa) toabout 80 psia (552 kPa).

In another embodiment, the invention is directed to a gas phase processfor polymerizing one or more hydrocarbon monomer(s) comprising producinga polymer product in the presence of a catalyst system and a condensingagent at temperature below the Critical Temperature optionally in aninsulated reactor and optionally for a period of 12 hours or more,wherein the catalysts system is a conventional-type transition metalcatalyst system, preferably a Ziegler-Natta-type catalyst system orPhillips type catalyst system, as previously defined, and the polymerproduct having a density in the range of from about 0.88 g/cc to about0.940 g/cc, preferably in the range of from about 0.900 g/cc to 0.940g/cc, and more preferably in the range of from about 0.910 g/cc to about0.930 g/cc, and a polymer production rate greater than 40,000 kg/hour,preferably greater than 55,000 kg/hour and most preferably greater than70,000 kg/hour. In a preferred embodiment, the gas phase processincludes a fluidizing medium that is introduced to a reactor, and theprocess is operating in a condensed mode wherein the level of condensingor condensed is greater than 18 weight percent, preferably greater than34 weight percent, and most preferably greater than 50 weight percentbased on the total weight of fluidizing medium being introduced into thereactor. In yet another embodiment, the partial pressure of thecondensable fluid is in the range of from 5 psia (35 kPa) to about 100psia (690 kPa), preferably in the range from about 10 psia (69 kPa) to90 psia (621 kPa), more preferably in the range of from 15 psia (103kPa) to about 80 psia (552 kPa), and most preferably in the range offrom 20 psia (138 kPa) to about 60 psia (414 kPa).

Polymers produced by the process of the invention are useful in suchforming operations as film, sheet, and fiber extrusion and co-extrusionas well as blow molding, injection molding and rotary molding. Filmsinclude blown or cast films formed by coextrusion or by lamination,shrink film, cling film, stretch film, sealing films, oriented films.The films are useful in snack packaging, heavy duty bags, grocery sacks,baked and frozen food packaging, medical packaging, industrial liners,membranes, etc. in food-contact and non-food contact applications.Fibers include melt spinning, solution spinning and melt blown fiberoperations for use in woven or non-woven form to make filters, diaperfabrics, medical garments, geotextiles, etc. Extruded articles includemedical tubing, wire and cable coatings, geomembranes, and pond liners.Molded articles include single and multi-layered constructions in theform of bottles, tanks, large hollow articles, rigid food containers andtoys, etc.

EXAMPLES

In order to provide a better understanding of the present inventionincluding representative advantages thereof, the following examples areoffered.

Density was measured in accordance with ASTM-D-1505-98.

Melt Index (MI), I21 and I2 were measured by ASTM D-1238-01.

DSC Peak melting point was measured as follows: 3 to 9 milligrams ofgranular polymer sample was charged into a 30 micro liter, aluminum,hermetically sealed capsule (Perkin Elmer part Number B0182901),weighed, and placed on the test stage of a DSC instrument. As isstandard practice in the DSC technique, a blank capsule was also placedon the reference stage. (If the test was to be done in the presence ofliquid, the test capsule was also charged with the liquid prior toclosing, or sealing, the capsule.) The DSC instrument was programmed tostart each test by first ramping down the temperature (of both capsules)at a rate of 5° C./min until reaching 0° C., and holding at thistemperature for 2 minutes. The temperature was then ramped up at a rateof 5° C./min. until reaching a final temperature of 150° C. During theramp-up in temperature, the differential heat flow required to heat thepolymer containing capsule was recorded. The polymer peak meltingtemperature was taken as the temperature at which the differential heatflow was at its highest value during the ramp-up.

The isopentane used in the examples was purified by passing it through abed of oxygen-removal catalyst (BASF R3-11) and then through a stackedbed of 3 A molecular sieves and Selexsorb CD.

The 1-hexene comonomer was purified by passing it through 3 A molecularsieves and then a bed of Selexsorb CD.

The ethylene was purified by passing it through a column containingoxygen removal catalyst (BASF R3-16), followed by a stacked columncontaining 3 A molecular sieves and Selexsorb CD.

The HFC-245fa was obtained from Honeywell, commercially available undertheir trade name Enovate 3000. The HFC-245fa was purified by passing itthrough a stacked column of 3 A molecular sieves, oxygen removalcatalyst (BASF R3-16), and Selexsorb CD.

Examples 1-3

A series of tests were performed on polymer samples to determine theCritical Temperatures for selected polymer solvent combinations.

In the following examples, the dry sticking temperature was measured byone or both of two methods. The first method involved fluidizing thepolymer sample in a medium scale fluidized bed reactor system. (Thismethod is referred to as the medium scale fluidization test). Testsconducted by this method were performed in a fluidized bed reactorequipped with a temperature control system, a differential pressure cellto monitor the polymer bed weight and quality of fluidization, and a GCanalyzer for monitoring the gas composition. The reactor consisted of acylindrical bed section of 15.2 cm diameter and 117 cm height, with aconical expanded section increasing to 25.4 cm diameter at the top ofthe reactor. Gas entered the fluidized bed through a perforateddistributor plate. For each test, the unit was charged withapproximately 2500 grams of polymer and fluidized using nitrogen gas ata reactor pressure of 2172 kPa, a fluidization velocity of 0.49 m/sec.,and a temperature of 79° C. With the reactor stabilized at theseconditions, a test was initiated by slowly increasing the temperature ata steady rate (of 4 to 5° C./hr) until fluidization was lost or themaximum unit operating temperature of 104° C. was reached. (The heatingsystem was limited to a maximum of 104° C.) When the test was completed,the reactor was cooled and the polymer was removed from the reactor. Ifthe polymer was free flowing and polymer material did not aggregate onthe reactor walls, it was concluded that the polymer dry stickingtemperature had not been reached (i.e. that the dry sticking temperaturewas greater than 104° C.). If the inspection of the reactor revealedthat the polymer had aggregated on the reactor wall, it was concludedthat the dry polymer sticking temperature had been reached; in whichcase the bed differential pressure readings were reviewed to determinethe temperature at which quality fluidization was lost as indicated by areduction in the noise (or bandwidth) in the readings from thedifferential pressure sensor. In the event that the differentialpressure cell did not indicate a loss in quality fluidization during thetemperature ramp up, but that the polymer had aggregated to the reactorwalls (as determined during the post run inspection), it was concludedthat the dry sticking temperature was approximately equal to the maximumtemperature achieved in the test (104° C.).

The second method used to determine polymer dry sticking temperatureinvolved a lab scale fluidization apparatus. (This method is referred toas the lab scale fluidization test.) The apparatus consisted of a glasscolumn of 5.1 cm diameter operated under atmospheric pressure andequipped with a glass frit to ensure even distribution of thefluidization gas. The column was surrounded by an electrical heatingjacket with an integral temperature regulator. Approximately 40 to 50grams of granular polymer was added to the column for each test. Thepolymer bed was fluidized using heated nitrogen gas. The polymer bedtemperature was measured using a thermocouple located approximately0.5-1.0 cm above the glass frit. The polymer in the column was initiallyheated to a starting temperature of 85 to 90° C. When the internaltemperature stabilized, the flow of nitrogen fluidizing gas was shut offfor 30 seconds and then restarted. The polymer bed was then inspectedfor signs of agglomeration or loss of fluidization (channeling). If noagglomeration or channeling was observed, the temperature was raised byapproximately 1-2° C. After the temperature stabilized at the new(higher) value, the nitrogen flow was again interrupted for 30 seconds,and then restarted. The polymer bed was again inspected for signs ofagglomeration or channeling. The test continued in this manner until thefluidization gas was observed to channel through the polymer bed or whenpolymer agglomeration was observed. The dry sticking temperature wastaken as the lowest temperature at which channeling or agglomerationfirst occurred.

Table 1 shows the I2, I21, and molded density values for the threeexamples along with a brief description of the polymer samples. Table 2shows the measured peak melting points for each sample. There are fourpeak melting points shown for each polymer sample, including the drypolymer peak melting point, the isobutane saturated polymer peak meltingpoint, the isopentane saturated polymer peak melting point, and theHFC-245fa saturated polymer peak melting point. Also included in Table 2is the dry polymer sticking temperature as determined by the mediumscale fluidization test (referred to as “Medium Scale” in the table) andas determined by the lab scale fluidization test (referred to as “LabScale” in the table). Table 3 shows the calculated melting pointdepressions for the polymer samples saturated with isobutane,isopentane, and HFC-245fa. Also shown in Table 3 are the calculatedcritical temperatures for a polymer/isobutane system, apolymer/isopentane system, and a polymer/HFC-245fa system.

Example 1

In this example the critical temperature was determined for a commercialgrade linear low density polyethylene sample produced from aconventional-type transition metal catalyst as described in Example A(below) with a hexene comonomer. The polymer I2 was 0.768 dg/min and themolded density was 0.9173 g/cc. The peak DSC melting point for the drypolymer was 125° C. and the melting point depression was measured as 18°C., 21° C., and 2° C. for isobutane, isopentane, and HFC-245fa,respectively. The polymer dry sticking temperature was determined to be104° C. in both the medium scale fluidization test and lab scalefluidization test. In the medium scale fluidization test there was noindication from the differential bed pressure cell that qualityfluidization was lost anytime during the temperature ramp-up; however,visual inspection of the reactor internals following the test showedpolymer aggregates caked on the reactor walls approximately 0.5 cmthick. As calculated from the melting point depression and the drypolymer sticking temperature and shown in Table 3, the criticaltemperature was determined to be 86° C. for a polymer/isobutane system,83° C. for a polymer/isopentane system, and 102° C. for apolymer/HFC-245fa system.

Example 2

In this example the critical temperature was determined for a bimodalpolyethylene resin sample produced from a metallocene-type transitionmetal catalyst as described in U.S. Pat. Nos. 6,242,545, 6,248,845 and6,528,597. The polymer I2 was 0.919 dg/min and the molded density was0.9184 g/cc. The peak DSC melting point for the dry polymer was 125° C.and the melting point depression was measured as 18° C., 23° C., and 3°C. for isobutane, isopentane, and HFC-245fa, respectively. The polymerdry sticking temperature was determined to be 107° C. in the lab scalefluidization test. (In this case the medium scale fluidization testproduced an inconclusive result with no indication of sticky resin,reduced DP bandwidth, or reactor fouling indicated at the highestavailable temperature of 104° C.) Taking the lab scale value of 107° C.as the dry sticking temperature, the critical temperature was determinedto be 89° C. for a polymer/isobutane system, 84° C. for apolymer/isopentane system, and 104° C. for a polymer/HFC-245fa system.

Example 3

In this example the critical temperature was determined for a commercialgrade polyethylene sample produced from a conventional-type transitionmetal catalyst as described in Example A with a butene comonomer. Thepolymer I2 was 1.16 dg/min and the molded density was 0.9188 g/cc. Thepeak DSC melting point for the dry polymer was 123° C. and the meltingpoint depression was measured as 19° C., 21° C., and 2° C. forisobutane, isopentane, and HFC-245fa, respectively. The polymer drysticking temperature was determined to be 104° C. in the medium scalefluidization test. In this test there was no indication from thedifferential bed pressure cell that quality fluidization was lostanytime during the temperature ramp-up; however, visual inspection ofthe reactor internals following the test showed polymer aggregates cakedon the reactor walls approximately 0.5 cm thick. As calculated from themelting point depression and the dry polymer sticking temperature andshown in Table 3, the critical temperature was determined to be 85° C.for a polymer/isobutane system, 83° C. for a polymer/isopentane system,and 102° C. for a polymer/HFC-245fa system.

TABLE 1 I2 I21 (ASTM (ASTM Density (molded) Example D1238-01) D1238-01)(ASTM D1505-98) No. Description [dg/min.] [dg/min.] [g/cc] 1 Z/N Hexene0.768 31.41 0.9173 Film (granules) 2 Bimodal 0.919 29.72 0.9184Metallocene (granules) 3 Z/N Butene 1.160 29.05 0.9188 Film (granules)

TABLE 2 Dry Isobutane Isopentane HFC-245fa Polymer Polymer PolymerPolymer Dry Melting Melting Melting Melting Sticking Dry Point PointPoint Point Temp. Sticking DSC peak DSC peak DSC peak DSC peak MediumTemp. Example melt melt melt melt Scale Lab Scale No. [° C.] [° C.] [°C.] [° C.] [° C.] [° C.] 1 125 108 104 123 104 104 2 125 107 102122 >104 107 3 123 103 102 121 104 N/A

TABLE 3 Melting Melting Melting point point point Critical CriticalCritical depression depression depression Temp. Temp. Temp. ExampleIsobutane Isopentane HFC-245fa Isobutane Isopentane HFC-245fa No. [° C.][° C.] [° C.] [° C.] [° C.] [° C.] 1 18 21 2 86 83 102 2 18 23 3 89 84104 3 19 21 2 85 83 102

Example A Preparation of a Conventional-Type Transition Metal Catalyst

A conventional-type transition metal catalyst was prepared from amixture of a magnesium compound, for example MgCl₂, a titanium compound,for example TiCl₃.⅓AlCl₃, and an electron donor, for exampletetrahydrofuran (THF), and was supported on silica that was dehydratedat 600° C. A detailed description of the preparation procedure can befound in U.S. Pat. No. 4,710,538, which is herein incorporated byreference. The specific catalyst formulation used had a TNHAL/THF moleratio of 0.27 and a DEAC/THF mole ratio of 0.50 where TNHAL istri-n-hexyl aluminum and DEAC is diethyl aluminum chloride.

Example B Preparation of a Metallocene-Type Transition Metal Catalyst

A bulky ligand metallocene-type catalyst system was prepared withdimethylsilyl-bis(tetrahydroindenyl)zirconium dichloride(Me₂Si(H₄Ind)₂ZrCl₂) available from Albemarle Corporation, Baton Rouge,La. and methylalumoxane, available from Albemarle, Baton Rouge, La. The(Me₂Si(H4Ind)₂ZrCl₂) catalyst compound was combined with a 30 weightpercent methylaluminoxane (MAO) in toluene and was supported onCrosfield ES-70 grade silica dehydrated at 600° C. having approximately1.0 weight percent water Loss on Ignition (LOI). LOI is measured bydetermining the weight loss of the support material which has beenheated and held at a temperature of about 1000° C. for about 22 hours.The Crosfield ES-70 grade silica has an average particle size of 40microns and is available from Crosfield Limited, Warrington, England.

Examples C, D, E and F

A series of tests were performed in a gas phase reactor to determine themaximum sustainable Induced Condensing Agent (ICA) concentration thatcould be achieved while maintaining stable fluidization. The tests werecarried out with two different ICA materials, isopentane and HFC-245fa.The total reactor pressure was maintained at 2169 kPa and an operatingtemperature of 85° C. Each test was started with no ICA in the reactor.Once operations stabilized and the unit was operating in steady stateconditions, the ICA was introduced into the reactor. The ICAconcentration was then ramped up to a target set-point or until thepolymer became sticky and it was no longer possible to remove polymerproduct from the reactor using standard operating procedures.

All of the medium scale tests of Examples C-F were done in a gas phasefluidized bed reactor equipped with devices for temperature control,catalyst feeding or injection equipment, GC analyzer for monitoring andcontrolling monomer and gas feeds and equipment for polymer sampling andcollecting. The reactor consisted of a 6″ (15.2 cm) diameter bed sectionincreasing to 10″ (25.4 cm) at the reactor top. Gas entered thefluidized bed through a perforated distributor plate. The reactor wasalso equipped with a product discharge system for removing polymerproduct from the reactor. A description of the operating conditions forthe tests is given in Table A.

Example C

In this example, the reactor was operated with the Ziegler Nattacatalyst of Example A with no ICA. The gas phase reactor reached steadystate producing a polymer product with a 0.917 g/cc density and a meltindex (I2) of 1.21 dg/min. Quality fluidization was maintainedthroughout the run and no problems were encountered with dischargingpolymer product from the reactor.

Example D

Similar reactor conditions were employed as in Example C except thatisopentane was used to as a conventional ICA. The isopentaneconcentration was first ramped up to 1.5 mole % and held for 24 hours.Following the 24 hour hold period, the isopentane was further ramped upto between 6 and 7 mole % over a 7 hour period. Above this ICAconcentration it was not possible to remove polymer product from thereactor using normal operating procedures. At ICA concentrations lowerthan 6 to 7 mole %, polymer product could be removed from the reactorusing normal operating procedures.

Example E

HFC-245fa was used as the ICA with the Ziegler Natta catalyst of ExampleA. Other reactor conditions were similar to those in Example C and D.The HFC-245fa concentration was ramped up from 0 mole % to 20.7 mole %over a 48 hour period. The initial ramp up to 4 mole % was carried outover 24 hours and the ramp up from 4 mole % to 20.7 mole % was carriedout over the remaining 24 hours. The maximum ICA concentration obtainedwas measured at 20.7 mole %. This was the highest concentrationattempted for this example. At the time an ICA concentration of 20.7mole % was reached, unrelated technically difficulties forced ashut-down of the unit. At ICA concentrations as high as 20.7 mole %,polymer product could be removed from the reactor using normal operatingprocedures and no polymer stickiness was observed.

Example F

HFC-245fa was used as the ICA with the metallocene catalyst of ExampleB. The HFC-245fa concentration was ramped up to 17.8 mole % over a 30hour period. The HFC-245fa concentration was first ramped up to between1 mole % and 2 mole % and held for 14 hours. Following the 14 hour holdperiod, the HFC-245fa concentration was further ramped up to 17.8 mole %over a 16 hour period. This concentration was then held for over 2 hoursand was the maximum ICA concentration measured for this example.Throughout this entire test polymer product could be removed from thereactor using normal operating procedures and no polymer stickiness wasobserved.

TABLE A Example Example C Example D Example E Example F Catalyst A A A BICA None Isopentane HFC-245fa HFC-245fa Reactor Bed Temperature (° C.)*85 85 85 79 Reactor Pressure (kPa)* 2169 2169 2169 2169 Ethylene PartialPressure (kPa)* 456 453 464 764 Hexene/Ethylene gas ratio 0.116 0.0710.101 0.034 (mole %/mole %)* Hydrogen/Ethylene gas ratio 0.191 0.1960.193 2.9E−04 (mole %/mole %)* Triethylaluminum Feed (g/hr)* 11.8 11.913.5 10.0 Production Rate (g/hr)* 421 645 380 287 Bed Weight (g)* 19381933 1849 1933 Residence Time (hr)* 4.6 3.0 4.9 6.7 Superficial GasVelocity (m/s)* 0.48 0.50 0.50 0.50 Product Density (g/cc) 0.917 0.9160.922 0.922 Product Melt Index - I2 (dg/min) 1.21 1.23 0.92 1.48 MaximumICA Concentration N/A 6 to 7 20.7 17.8 Achieved under Stable Fluid BedOperations (mole %) *Four hour average,

Discussion of Examples C, D, E and F

Examples C and D illustrate the conventional practice of operating gasphase fluid bed polymerization reactors at reactor temperatures greaterthan the Critical Temperature. In both Examples C and D the reactortemperature was operated at 85° C., whereas the Critical Temperature wasapproximately 83° C. This value was taken from the results of Example 1with isopentane (as shown in Table 3), since the product properties(density and I2) of the resin sample used in Example 1 were similar tothose of the resin produced in Examples C and D. Such conventionaloperation above the critical temperature may lead to resin stickingand/or agglomeration as illustrated by Example D. In that case,relatively high concentrations of isopentane (in combination with thehexene comonomer) induced stickiness in the produce as evidenced by theinability to discharge polymer product from the reactor at isopentaneconcentrations greater than 6-7 mole % (130-152 kPa).

Examples E and F illustrate the present invention of operation below theCritical Temperature. In Example E, the reactor temperature was 85° C.,and the Critical Temperature (with HFC-245fa) was approximately 102° C.In Example F, the reactor temperature was 79° C., and the CriticalTemperature was approximately 102° C. (Table 3). These values ofCritical Temperature was taken from the results of Examples 1 and 3 withHFC-245fa (shown in Table 3), since the product properties (density andI2) of the resin samples used in Examples 1 and 3 were similar to thoseproduced in Examples E and F. The results from these examples (E and F)show that operation below the Critical Temperature allows much higherconcentrations of ICA without inducing stickiness or agglomeration inthe resin product. This is best seen in a direct comparison with thesame resin grade (the Ziegler-Natta hexene film grade) provided byExamples D and E. In Example D (operation above the CriticalTemperature) the limiting ICA concentration was 6-7 mole % (130-152kPa). In Example E (operation below the Critical Temperature) thelimiting ICA concentration was not reached, even with ICA concentrationsas high as 20.7 mole % (449 kPa). Such higher concentrations of ICAallow higher dew point temperatures in the reactor and correspondinglyhigher condensed mode production rates.

While the present invention has been described and illustrated byreference to particular embodiments, those of ordinary skill in the artwill appreciate that the invention lends itself to variations notnecessarily illustrated herein. For example, it is contemplated thatother halogenated fluorocarbons alone or in combination with afluorinated hydrocarbon as herein described would be useful in theprocess of the invention. It is also within the scope of this inventionthat the gas phase process of the invention can be operated in series,with two or more reactors, each reactor operating in a gas phase or oneof the reactors operating in a slurry phase. For this reason, then,reference should be made solely to the appended claims for purposes ofdetermining the true scope of the present invention.

All documents described herein are incorporated by reference herein,including any priority documents and/or testing procedures, except tothe extent they are inconsistent with this specification.

1. A continuous gas phase process comprising polymerizing one or morehydrocarbon monomer(s) in a fluidized bed reactor in the presence ofZiegler-Natta-type catalyst system and a condensable fluid for a periodof at least 12 hours where the bed temperature is less than the CriticalTemperature and the dew point temperature of the gas composition in thereactor is within 25° C. of the bed temperature.
 2. The process of claim1, wherein the process is operated in condensed mode.
 3. The process ofclaim 1, wherein the reactor is insulated.
 4. The process of claim 2,wherein the reactor is insulated.
 5. The process of claim 1, wherein thecondensable fluid comprises a C3 to C10 hydrocarbon, a fluorinatedhydrocarbon or a combination thereof.
 6. The process of claim 1, wherethe dew point temperature of the gas composition in the reactor iswithin 20° C. of the bed temperature.
 7. The process of claim 6, wherethe dew point temperature of the gas composition in the reactor iswithin 15° C. of the bed temperature.
 8. The process of claim 6, wherethe dew point temperature of the gas composition in the reactor iswithin 10° C. of the bed temperature.
 9. The process of claim 6, wherethe dew point temperature of the gas composition in the reactor iswithin 5° C. of the bed temperature.
 10. The process of claim 1, whereinthe process comprises the steps of: (a) introducing a recycle streaminto the reactor, the recycle stream comprising one or more monomer(s);(b) introducing a polymerization catalyst and a condensable fluid intothe reactor where the bed temperature is less than the CriticalTemperature and the dew point temperature of the gas composition in thereactor is within 25° C. of the bed temperature; (c) withdrawing therecycle stream from the reactor; (d) cooling the recycle stream to forma gas phase and a liquid phase; (e) reintroducing the gas phase and theliquid phase, separately, and/or in combination, into the reactor; (f)introducing into the reactor additional monomer(s) to replace themonomer(s) polymerized; and (g) withdrawing a polymer from the reactor.11. The process of claim 10, wherein the process is operated in thecondensed mode.
 12. The process of claim 10, wherein polymer iswithdrawn in step (g) at a rate of at least 50,000 lb/hour.
 13. Theprocess of claim 1, wherein the gas phase polymerization is operated ina condensed mode in which a liquid and a gas are introduced to afluidized bed reactor having a fluidizing medium, wherein the level ofcondensable fluid is greater than 1 weight percent based on the totalweight of the liquid and gas entering the reactor.
 14. The process ofclaim 13, wherein the level of condensable fluid is greater than 2weight percent.
 15. The process of claim 13, wherein the level ofcondensable fluid is greater than 10 weight percent.
 16. The process ofclaim 13, wherein the level of condensable fluid is greater than 25weight percent.
 17. The process of claim 13, wherein the level ofcondensable fluid is greater than 30 weight percent.
 18. The process ofclaim 1, where the condensable fluid comprises a C2 to C10 saturated orunsaturated hydrocarbon.
 19. The process of claim 1, wherein thecondensable fluid comprises one or more of propane, n-butane, isobutane,n-pentane, isopentane, neopentane, n-hexane, isohexane, n-heptane, orn-octane.
 20. A continuous gas phase process comprising polymerizing oneor more hydrocarbon monomer(s) in a fluidized bed reactor in thepresence of Ziegler-Natta-type catalyst system and a condensable fluidfor a period of at least 12 hours where the bed temperature is less thanthe Z Temperature and the dew point temperature of the gas compositionin the reactor is within 25° C. of the bed temperature, where the ZTemperature is equal to the heat seal initiation temperature minus themelting point depression of the polymer to be made.
 21. A continuous gasphase process comprising polymerizing one or more hydrocarbon monomer(s)in a fluidized bed reactor in the presence of Ziegler-Natta-typecatalyst system and a condensable fluid for a period of at least 12hours where the bed temperature is less than the Q Temperature and thedew point temperature of the gas composition in the reactor is within 25° C. of the bed temperature, where the Q Temperature is equal to the hottack initiation temperature minus the melting point depression of thepolymer to be made.
 22. The process of claim 21, wherein the process isoperated in condensed mode.
 23. The process of claim 1, wherein theZiegler-Natta-type catalyst system comprises a Groups 4 to 6 transitionmetal compound.
 24. The process of claim 20, wherein theZiegler-Natta-type catalyst system comprises a Groups 4 to 6 transitionmetal compound.
 25. The process of claim 21, wherein theZiegler-Natta-type catalyst system comprises a Groups 4 to 6 transitionmetal compound.